Layered Strata Research Articles

Clay minerals of Shiranish Formation in, Erbil, Duhok northern Iraq

In the Upper Cretaceous of northern Iraq (upper Campanian-Maastrichtian), the Shiranish Formation is examined for clay minerals using X-ray diffraction in the Duhok (Sandor section) and Erbil cities (Lailuk section). In the marl section of the Shiranish Formation, the layers of chlorite, illite, kaolinite, palygorskite, and a mixed layer of montmorillonite-chlorite strata were discovered to have formed antigenically. The variation in minerals indicates the Cretaceous’ changing climate. Palygorskite is a result of leaching processes that are more successful due to variations in the parent rocks. The transition of palygorskite from montmorillonite and illite can occasionally be impacted by post-depositional diagenetic processes. Because of the warm conditions that supply the eroded clastic materials from earlier successions of Cretaceous in the area, chlorite, mixed-layers, and illite may have predominated over kaolinite. The variation in source rocks and drainage conditions is reflected in the variation of clay minerals in the investigated sequence, which could improve leaching rate processes.

AI methods application for classifying stratigraphic layers of snow cover with Snow micro pen device

In this work, AI methods were used to classify stratigraphic layers of the snow strata using measurements from the snow micro pen device. The data from the device were processed and the classified stratigraphic layers of the snow strata were compared with the direct snow pitting data. In the future, it was possible to classify stratigraphic layers of the snow strata using the available classified data of the device by the K-nearest neighbours clustering method according to the newly obtained data of the device without additional manual pitting.

Performance evaluation of alternative drainage material for landfill cover systems in combination with geosynthetics

The pursuit of sustainable development has prompted increased utilization of alternative materials in landfill cover systems. Despite evaluating these materials for hydraulic and strength properties, their performance with geosynthetics remains inadequately explored. This study focuses on investigating the use of recycled asphalt pavement (RAP) as an alternative drainage material and determining the interface friction angle between the drainage layer and the geomembrane through large-scale direct shear tests. Further, a numerical model of a municipal solid waste landfill in Italy was developed using Finite Element Method (FEM) software. Model validation was achieved by applying analytical two-wedge theory of veneer shear failure in layered strata. The study demonstrates a superior performance of RAP aggregates as drainage layer materials as compared to natural aggregates. It also emphasizes the importance of site-specific parameter determination and precise interface property characterization. Limitations of use of commercial software in identification of weak interfaces has also been highlighted.

Dynamic mechanical properties and failure characteristics of layered composite rock containing a tunnel-shaped hole

To investigate the dynamic mechanical properties and failure characteristics of the surrounding rock mass in layered strata, composite specimens with a circular hole and a horseshoe-shaped hole were prepared using rock-like materials. Then, the split Hopkinson pressure bar (SHPB) test system and digital image correlation (DIC) technology were employed to conduct relevant experiments and analyses. The experimental results indicate that the influence of cross-sectional shape differences on the dynamic mechanical properties of composite specimens cannot be ignored. Compared to composite specimens with a circular hole, the composite specimens with a horseshoe-shaped hole have a more significant hindrance to wave propagation, and their dynamic compressive strength (DCS) and elastic deformation ability are also lower. In addition, the bedding inclination θ also has a significant impact on the dynamic mechanical properties. With increasing bedding inclination θ, the DCS of composite specimens shows a trend of increasing–decreasing-increasing. Moreover, the energy proportion was analyzed according to the experimental results. This study also investigated the failure characteristics of tunnels surrounding rock in layered strata. For composite specimens with a circular hole, four types of cracking and their distribution related to the dip angle of bedding planes were summarized. For composite specimens with a horseshoe-shaped hole, six types of cracking and their distribution versus the bedding inclination were summarized.

Spatial Variation Law of Blasting Vibration in Layered Strata under Blasting Excavation of Subway Tunnel

Blasting vibration generated from blasting excavation of subway tunnel may endanger the adjacent structures buried in strata. To guarantee their safety and stability, it is crucial to understand the spatial variation law of blasting vibration in strata. In this paper, the blasting excavation of the large cross-sectional tunnel of Wuhan Metro Line 8 is studied. Three-dimensional finite element simulation is performed using the dynamic finite element program LS-DYNA, and its validity is verified by the field monitoring data. The spatial variation law of blasting vibration in layered strata is investigated through analyzed the distribution characteristic of blasting vibration in three directions, including the direction along the axis of the large cross-sectional tunnel, the direction perpendicular to the axis of the large cross-sectional tunnel, and the direction along the depth. A prediction model for blasting vibration velocity, which considers the impact of elevation differences, is established through dimensional analysis, enabling the prediction of blasting-induced vibrations at various depths in the layered strata.

Modulation of charge properties inside thin-film composite polyamide membranes towards enhanced nanofiltration performance

Nanofiltration (NF) is receiving increasing attention worldwide as a high-efficiency technology for water purification. One viable approach to enhance the performance of NF membranes involves the meticulous optimization of their physicochemical and structural attributes through the introduction of additives. Nonetheless, the predominant NF membrane additives currently accessible primarily exert their influence at the membrane's surface. In this context, we introduce a novel strategy for fabricating polyamide (PA) NF membranes endowed with augmented negative charge density, capable of permeating the innermost stratum of the separation layer. This innovation hinges on the straightforward inclusion of 2-Methylimidazole (Hmim) into the aqueous phase. The ramifications of Hmim's incorporation of the structural configuration, morphological composition, physicochemical characteristics, and overall performance of the thin-film composite (TFC) membrane were meticulously scrutinized through an array of comprehensive characterizations. The integration of Hmim affords PA nanofiltration membranes the remarkable capability to achieve a rejection rate as formidable as 99.5% for Na2SO4 and 42.8% for NaCl, all the while maintaining an unswerving flux. As a result, a high SO42-/Cl- separation factor of up to 116.1 was achieved. Our work provides insights and directions for the development of additives in the preparation of NF membranes.

Aeolian sand cover affects the soil hydrothermal state and permafrost degradation on the Qinghai-Tibet Plateau

Aeolian sand significantly affects permafrost degradation, but the effect of the aeolian sand on the permafrost on the Qinghai-Tibet Plateau remains unknown. The sand layer thickness is critical to its role. However, little quantitative research has been conducted on the effect of the sand layer thickness on its role. In this study, using CoupModel, we investigated the differences in the impact of the aeolian sand cover on the hydrothermal state of permafrost with 20 different sand layer thicknesses (10 ∼ 200 cm, 10 cm increment) and analyzed the mechanisms that explain the different impacts. The results reveal that the active layer is where the aeolian sand has the most impact on the permafrost. The aeolian sand layer accumulates precipitation into the soil below the sand, thereby significantly drying the shallow soil layer of the current stratum. Moreover, the thicker the sand layer, the more water accumulates in the underlying soil layer. In the middle-upper active layer, the initial soil heat storage, soil heat flow interception, and liquid water and ice contents govern the soil temperatures that increase in cold seasons and decrease in warm seasons as the sand layer thickens. Near the bottom of the active layer, the initial soil heat storage and soil heat flow interception control the soil temperatures that increase in cold seasons but fluctuate between sand layer thicknesses of 50 cm, 70 cm, and 120 cm in warm seasons as the sand layer thickens. Permafrost degradation is enhanced by sand layers thinner than 150 cm and retarded by sand layers thicker than 150 cm, respectively. The thermal state, soil properties, and accumulation process of the aeolian sand also contribute to this effect of the aeolian sand on the permafrost. In the plateau aeolian deserts, the sparse vegetation promotes permafrost degradation and the thinner seasonal snow cover protects permafrost. Moreover, under the different climate during the geological history period, the island or discontinuous permafrost might be formed due to the pluvial-radiation talik caused by the thicker sand layer or dunes.

Calculation of groundwater reserves for water withdrawal in layered strata

Calculation of groundwater reserves for water withdrawal in layered strata

Physical modelling of deformation and failure mechanisms and supporting effects for a deep-buried tunnel in inclined layered strata

Physical modelling of deformation and failure mechanisms and supporting effects for a deep-buried tunnel in inclined layered strata

Ladies in armor: A micro-computed tomographic study of skin calcification in European toads (genus Bufo).

Micro-computed tomography is a powerful tool toward the detailed reconstruction of internal and external morphology, in particular for ossified and other dense tissues. Here, we document and compare the level of calcification in the skin of the head and the parotoids (the external skin glands) in males and females of common and spined toads, Bufo bufo and B. spinosus. In some anurans, including Bufo species, a specific acellular calcified tissue layer within the dermis has been documented (the Eberth-Katschenko, or EK-layer). By a combination of micro-computed tomography and classical histology, we detected additional calcium deposits located in the dermal layer stratum spongiosum, positioned above the EK-layer. We showed that the level of calcification and the presence of additional calcium deposits are size and sex related, increasing in the order B. bufo males, B. spinosus males, B. bufo females to B. spinosus females. The last of these groups is the least variable. Bufo spinosus females have dense calcium deposits in the parotoids and the dorsal and ventral skin. Three-dimensional volume renderings and cross-sectional slices obtained by micro-CT scanning indicate that this approach is a promising technique for further studies on bufonid skin anatomy and geographic variation in skin calcification.

GPR results for indicating layers of snow strata

The authors of this article describe the results of GPR tests for indicating the layers of snow strata and determining their properties, allowing for forecasting of avalanche hazards. The GPR tests were carried out during the winter season 2021/2022. Trenches were dug in the snow, in the wall of which long metal rods (markers) were installed, which are the reflectors for the GPR and make it possible to distinguish the boundaries of layers on the radarogram. As a result of conducting GPR sounding of the snow cover, radarograms were obtained, on which the layered structure of snow can be read. Using the GeoScan32 software, dielectric permittivity values were obtained for 19 layers of snow strata with different properties. Correlations were obtained between dielectric permittivity and temperature, crystal diameter, snow layer density, and snow layer water storage. The resulting dielectric permittivity relationships reveal the strongest correlations between dielectric permittivity and density, with a higher correlation coefficient for dry snow than for wet snow. The values of dielectric permittivity obtained from GPR were also compared with calculated values derived from a number of empirical correlations with snow density.

INVESTIGATION OF THE STRESS STATE OF MINE WORKINGS USING METHODS OF DEFORMABLE SOLID MECHANICS

The assessment of the reliability of a mining and technological scheme, taking into account the stress state of mine workings, depends on a combination of mining and geological, technical and technological factors. The article demonstrates the creation of a model of a rock mass and a scheme for calculating the stress state based on modern methods of mechanics of a deformable solid body.The object of study is a single mine working of great length, passed through the rock parallel to the strike of the coal seam (field drift) and located in the zone of influence of the support pressure. Due to the fact that the field drift is laid in the soil of the formation, which is a layered stratum in the zone of influence of clearing operations, the predominant load is the bearing pressure on the formation. The areas of application of the methods of complex potentials of integral equations and their combinations in solving applied problems are determined. The data of mine (field) measurements and observations, laboratory experiments and their generalizations are taken into account both when setting tasks and assigning boundary conditions, and when checking the results obtained. The mixed problem of the theory of elasticity about the contact stress on half-strips with varying along the longitudinal axis was solved; moving away from the ends, deformative properties, when these half-strips are clamped with friction between the layered half-planes.

Polyethylene microplastics increases the tissue damage caused by 4-nonylphenol in the common carp (Cyprinus carpio) juvenile

Plastic particles have the ability to transfer harmful chemical pollutants due to their high adsorption capacity. Therefore, this study aimed to investigate the effects of combined exposure to polyethylene microplastics (PE-MPs) and 4-nonylphenol (4-NP) on juvenile common carp (Cyprinus carpio) using histopathological and histochemical biomarkers. Fish were separated into a control group and three treatment groups (10 mg/L PE-MPs; 10 mg/L PE-MPs + 200 µg/L 4-NP; 200 µg/L 4-NP) for a two-week continuous exposure experiment followed by two weeks of recovery. The three treatment groups showed histopathological changes compared to the control. These alterations included severe edema, lifting of the outer epithelium, interlamellar fusion and vacuolation, secondary lamellar shortening and complete fusion, increased mucous cell numbers in the gill tissue, enlargement of inner layer stratum periventricular, cell degeneration with pyknotic nuclei, increased blood capillaries, spongiosis in the brain tissue (optic tectum), central vein hemorrhage, shrunken and fatty degeneration of hepatocytes, rosette shapes around small congested blood sinusoids, vacuoles, necrosis, and severe glycogen reduction in the liver tissue. Some tissue changes improved during the two-week recovery period but did not return to normal. In conclusion, the mixture exposure of the PE-MPs and 4-NP on fish carp induced some histological alterations in most studied tissues and post-exposure made improvement in cellular and tissue structure.

EHDA engineering of Piroxicam-PVP components for pharmaceutical dosages

This study aimed to prepare piroxicam loaded polyvinyl pyrollidone (PVP) particulate mat, fabricated mat incorporated tablets and coated polyvinyl alcohol (PVA) films. The mat, engineered by using electrohydrodynamic atomisation (EHDA) technique, was evaluated for morphological features and particle size using scanning electron microscopy. In vitro drug release, ex vivo skin permeation and in vivo anti-inflammatory studies of oral (i.e., tablets) and topical (i.e., films) dosage forms were conducted to assess the efficiency of prepared formulations. The EHDA processed piroxicam-PVP components exhibited spherical shape, uniform surface and particle size of 3.67 ± 0.70 μm. The piroxicam mat incorporated oral and coated topical formulations exhibited release percentage of 73.79 ± 1.9% and 80.11 ± 2.3% respectively over a time period of 180 min. During ex vivo permeation study, treatment of rat skin using 500 μm microneedles led to a higher permeation of piroxicam (from coated films i.e., 75.54 ± 2.2% as compared to unpierced skin i.e., 58.23 ± 2.7% with a gradient of 0.28 and 0.21 respectively within 240 min. During in vivo anti-inflammatory study, a 52.58 ± 3.2% decrease in paw inflammation was observed in mat incorporated tablets administered group within 360 min. In comparison, topical application of coated films led to a 67.28 ± 2.9% decrease in inflammation. Microneedle treatment followed by topical application of coated films resulted in an 81.43 ± 3.1% reduction in paw inflammation over 360 min. Micropiercing of the skin resulted in breaching of uppermost skin barrier layer stratum corneum leading to an increased piroxicam permeation and rapid therapeutic response. It was concluded that EHDA processed mat incorporated tablets and coated topical films can serve as a promising choice for improving the solubility of poorly soluble piroxicam and oral/topical anti-inflammatory therapy.

Synaptic inputs to displaced intrinsically-photosensitive ganglion cells in macaque retina

Ganglion cells are the projection neurons of the retina. Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin and also receive input from rods and cones via bipolar cells and amacrine cells. In primates, multiple types of ipRGCs have been identified. The ipRGCs with somas in the ganglion cell layer have been studied extensively, but less is known about those with somas in the inner nuclear layer, the “displaced” cells. To investigate their synaptic inputs, three sets of horizontal, ultrathin sections through central macaque retina were collected using serial block-face scanning electron microscopy. One displaced ipRGC received nearly all of its excitatory inputs from ON bipolar cells and would therefore be expected to have ON responses to light. In each of the three volumes, there was also at least one cell that had a large soma in the inner nuclear layer, varicose axons and dendrites with a large diameter that formed large, extremely sparse arbor in the outermost stratum of the inner plexiform layer. They were identified as the displaced M1 type of ipRGCs based on this morphology and on the high density of granules in their somas. They received extensive input from amacrine cells, including the dopaminergic type. The vast majority of their excitatory inputs were from OFF bipolar cells, including two subtypes with extensive input from the primary rod pathway. They would be expected to have OFF responses to light stimuli below the threshold for melanopsin or soon after the offset of a light stimulus.

Microseismic energy distribution and impact risk analysis of complex heterogeneous spatial evolution of extra-thick layered strata

In the process of deep mining of coal resources, coal seams with better geological conditions are gradually mined preferentially, and the safe and efficient mining of working face in complex and heterogeneous spaces of residual coal seams is an urgent problem to be solved.. Based on the Kuangou Coal Mine as the background, using microseismic monitoring instruments and pressure sensor monitoring systems, the rock pressure appearance and microseismic energy characteristics accompanying the evolution of the overburden strata structure in the mining of solid coal and the lower working face of the gob are analyzed. Research on the precursory characteristics and early warning of micro-earthquakes. The research results show that: (1) The period of the W1123 working face mining under solid coal is relatively frequent, and the energy of microseismic events is higher than that under the mined-out area. However, the overlying rock structure under the gob is loose, broken and easy to move, showing obvious "high frequency-low energy" characteristics. (2) Extremely low values of the number and energy of microseismic events occurrs in the first 3 to 5 days of the rockburst event in the working face, and the locations of the rockburst disaster in the mine were generally distributed at the edge of the low-density area of the microseismic event. The accuracy of rockburst prediction is effectively improved through multi-parameter comprehensive early warning. (3) Roof deep hole blasting and roof cutting pressure relief weaken the roof energy accumulation and the concentrated release of rock formation energy, reduce the roof activity intensity in the microseismic event gathering area, and reduce the occurrence of large-energy events, which will easily induce large shock hazards. The energy event weakens into a slow release of multiple small energy events. This research provides a reference for the safe and efficient mining of working faces in complex space environment.

Sustainability of Heavily Loaded Raft Foundations on Granular Soils of Arabian Peninsula with Soft Clay Layer

Sandy soil formations are widespread around the globe, particularly in the Arabian Peninsula. The Sandy formations were created as a result of long-term geological activities including but not limited to alluvial and wind deposition. Since the alluvial deposits contain fine soils, the clay layers are often intercepted in the foundation supporting strata. The geotechnical foundation design based on field and lab investigations usually relies on the average response of the layered strata and can satisfy both shear and settlement criteria. However, the enduring sustainability of the heavily loaded foundations is required to be investigated in detail. In this study FEM based numerical investigations have been carried out on a thin raft foundation resting on granular soil, with a soft clay layer in the influence zone. The COMSOL Multi-physics platform has been used for the analysis. The study cases are planned based on the thickness of the clay layer and building load. The analysis results predict the risk involved in the sustainability of rafts in terms of the settlement. The field engineers and designers are recommended to consider the risk and plan accordingly

Journalism and Democratic Backsliding: Critical Realism as a Diagnostic and Prescription for Reform

ABSTRACT Renewed scrutiny of how U.S. journalism functions as a political institution is warranted in an era of democratic backsliding. While news media cannot deliver policy on their own, they are fully equipped to represent, interpret, and amplify grievance. If disaffection is directed at retribution rather than policy, journalism contributes to backsliding in the further pathologizing of (non)-responsive government. This essay proposes critical realism (CR) as a heuristic for conceptualizing unique contributions of news media to backsliding. Reality consists of layered strata in CR. This approach accepts the premise of news as a social construction but maintains that a domain of reality exists independent of discursive representation, and that this realm can be actualized in ways that are damaging to democracy. Applied to political communication, the domain of the real includes democratic deficits that may or may not become actualized depending on how journalism operates at the empirical level. Critical realism also generates insights applicable to reform. CR insists that journalists avoid reifying sentiment in ways that comfort authoritarians. The diagnostic acknowledges the journalistic conviction that an external reality is knowable, positing nevertheless that the news interacts with underlying social forces. The profession must forge a healthier relationship with the public to avoid reifying audience support for anti-democratic norms. Reflexivity could be directed beyond the recognition of complicity to two productive rationales for safeguarding democracy: liberal multiculturalism and journalistic paternalism. A final section offers a framework for future research in tracing linkages between journalistic practice and backsliding.

Gas extraction technology and application of near horizontal high directional drilling

In order to solve the problem of gas accumulation in the upper corner caused by large gas emission due to high mining intensity in the fully mechanized top coal caving face of Wangjialing coal mine, we used numerical simulation method combined with the key stratum layer control theory to study the roof caving trend and development law of inclined mining fissure. Then we analyzed the evolution process of goaf fissure with the advance of the working face and the development height of roof fissure. Finally, we got the best hole layout position and drilling structure of near horizontal high-level directional long drilling. The practice indicates that we achieved nice gas extraction effect by setting near horizontal high-level directional long drilling borehole according to the above research results. The maximum net extraction volume of a single borehole is 2.10 m3/min, the maximum extraction volume fraction is 31.39%, and the total net amount of gas extracted from the four boreholes under construction is 289900 m3. The gas concentration in the upper corner of the working face decreased to 0.46% during extraction, and the problem of gas overrun in the upper corner was effectively solved.

Numerical simulation of hydraulic fracture height layer-through propagation based on three-dimensional lattice method

Unconventional reservoirs such as shale and coal rock are generally well-bedded, with significant differences in the interlayer stress and rock physical parameters. The change law of the fracture morphology is difficult to predict after the layer-through propagation of the fracture height during the fracturing operation. Existing studies have widely used multilayered two-dimensional fracture height models, which are not suitable for fracture propagation simulation in unconventional reservoirs under complex geological conditions. This study established a fracture height propagation model based on the three-dimensional (3D) discrete lattice method and used the Xsite software to simulate the layer-through propagation in layered strata under the influence of in-situ stress, rock physical properties, and construction parameters. The effects of different factors on the fracture height and fracture morphology are described. Sensitivity analysis for different model cases revealed that, when the fractures entered a formation with high in-situ stress and fracture toughness, the growth of the fracture height was restrained. As the elastic modulus of the rock increased, the fracture width significantly decreased and the fracture height increased. Increasing the fracturing fluid displacement benefits the growth of the fracture height and width, and accelerates the passage of hydraulic fracture through the interlayer interface to achieve deep penetration reconstruction in the longitudinal direction of the reservoir. Higher fracturing fluid viscosity increases the fracture width and reduces the fracture reconstruction volume, and the fracture morphology changes under different fracturing fluid viscosity. This study is useful for improving and supplementing unconventional reservoir fracture height simulation technology.