Search Results (1,407)

Acrobeloides nanus is a cosmopolitan, parthenogenetic soil nematode that is widely distributed across various terrestrial environments, including forests, sand dunes, and agricultural lands. In Korea, this nematode was first isolated from soil collected from a potato farm. It has been used as a biological indicator for monitoring contamination caused by divalent metals such as copper and zinc. In this study, A. nanus was isolated from the soil collected from a cucumber farm, and its identity was confirmed using both morphological and molecular markers. Spray-induced gene silencing using double-stranded RNA (dsRNA) represents a promising new strategy for pest control. Here, we tested a spraying dsRNA that would specifically suppress the target genes in A. nanus. Three genes (Pat-10, Unc-87, and vATPase-B) were targeted, and their expression levels were assessed following treatment with their corresponding dsRNAs. The dsRNAs were sprayed onto the nematode diet. As the concentration of dsRNA increased, the expression levels of the target genes were significantly reduced, leading to notable nematode mortality. However, nematicidal activity varied among the three different dsRNAs. To practically assess these dsRNAs under field conditions, the dsRNAs were applied to the soil containing the nematodes by a drenching application. Significant mortality was observed in treatments with dsRNAs targeting vATPase-B or Pat-10, but not with dsRNA targeting Unc-87. To enhance nematicidal activity in soil, the dsRNAs were formulated with chitosan. This formulation significantly improved the stability of dsRNAs under soil conditions and increased their control efficacy against A. nanus. This study suggests that the drenching technique offers an effective strategy to the control of soil-dwelling nematode pests affecting agricultural crops. Full article

A multidisciplinary investigation was conducted in southwestern Sicily, near the seismically active Belice Valley, based on the analysis of morphostructural features. These were observed as open fractures between 2014 and 2017; they were subsequently filled anthropogenically and then reactivated during a seismic swarm in 2019. We generated a seismic event distribution map to analyze the location, magnitude, and depth of earthquakes. This analysis, combined with multitemporal satellite imagery, allowed us to investigate the spatial and temporal relationship between seismic activity and fracture evolution. To investigate the spatial variation in thickness of the superficial cover and to assess the depth to the underlying bedrock or stiffer substratum, 45 Horizontal-to-Vertical Spectral Ratio (HVSR) ambient noise measurements were conducted. This method, which analyzes the resonance frequency of the ground, produced maps of the amplitude, frequency, and vulnerability index of the ground (K_g). By inverting the HVSR curves, constrained by Multichannel Analysis of Surface Waves (MASW) results, a subsurface model was created aimed at supporting the structural interpretation by highlighting variations in sediment thickness potentially associated with fault-controlled subsidence or deformation zones. The surface investigation revealed depressed elliptical deformation zones, where mainly sands outcrop. Grain-size and morphoscopic analyses of sediment samples helped understand the processes generating these shapes and predict future surface deformation. These elliptical shapes recall the liquefaction process. To investigate the potential presence of subsurface fluids that could have contributed to this process, Electrical Resistivity Tomography (ERT) was performed. The combination of the maps revealed a correlation between seismic activity and surface deformation, and the fractures observed were interpreted as inherited tectonic and/or geomorphological structures. Full article

The assessment of microplastics (MPs) in terrestrial ecosystems has garnered increasing global attention due to their accumulation and migration in soils, which may have potential impacts on soil health, biodiversity, and agricultural productivity. However, research on their distribution and interactions in soil remains limited, especially in tropical regions. This study aimed to characterize MPs extracted from tropical soil samples and relate their abundance to soil and terrain attributes under different land uses (forest, grassland, and agriculture). Soil samples were collected from an experimental farm in Lavras, Minas Gerais, Southeastern Brazil, to determine soil physical and chemical attributes and MP abundance in a micro-watershed. These locations were also used to obtain terrain attributes from a digital elevation model and the normalized difference vegetation index (NDVI). The majority of microplastics found in all samples were identified as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), and vinyl polychloride (PVC). The spatial distribution of MP was rather heterogeneous, with average abundances of 3826, 2553, and 3406 pieces kg⁻¹ under forest, grassland, and agriculture, respectively. MP abundance was positively related to macroporosity and sand content and negatively related to clay content and most chemical attributes. Regarding terrain attributes, MP abundance was negatively correlated with plan curvature, convergence index, and vertical distance to channel network, and positively related to topographic wetness index. These findings indicate that continuous water fluxes at both the landscape and soil surface scales play a key role, suggesting a tendency for higher MP accumulation in lower-lying areas and soils with greater porosity. These conditions promote MP transport and accumulation through surface runoff and facilitate their entry into the soil. Full article

Overpressure systems in the Qingshankou Formation of the Gulong Sag have a significant impact on unconventional shale oil accumulation, but their distribution and genesis are unknown. This study uses a comparative analysis of three primary pressure prediction methods—the equivalent depth method, the Eaton method, and the Bowers method—to investigate the genetic mechanisms of overpressure and their controlling factors. The study clarifies the link between overpressure and hydrocarbon distribution. The key findings are as follows. (1) The Eaton method is identified as the best approach for estimating current formation pore pressure. The Qingshankou Formation exhibits mild overpressure development, with a maximum pressure coefficient of 1.44. (2) Hydrocarbon-generating overpressure, driven by source rock maturation, is confirmed as the dominant mechanism through integrated acoustic velocity–density cross plots and logging analysis. (3) Tectonic-sedimentary factors, such as burial depth, source rock thickness, sand-mud ratio, and faults, collectively control the spatial variability of overpressure. (4) The distribution of the Gulong shale oil and the Fuyu tight oil is influenced by overpressure, with the northwestern part of the sag and the adjacent sand bodies being the respectively favorable areas. These results lay the groundwork for accurately reconstructing paleopressure and better understanding the hydrocarbon accumulation potential of shale oil and Fuyu tight oil. They also provide guidance on the exploration and development of unconventional resources. Full article

Straw checkerboard sand barriers play a critical role in wind erosion control and dune stabilization. However, manual installation remains predominant, leading to low efficiency and inconsistent quality. To address this, a compact integrated machine was developed for straw checkerboard laying and pressing using rice straw. The design emphasizes the coordinated function of the straw distribution and pressing systems. Physical parameters of rice straw—average bundle length (<120 cm), repose angle (20.95°), and elastic modulus (1.65 MPa)—were measured to guide structural design. A 3D model of the machine and a multibody dynamic simulation of the distribution system were conducted to validate the mechanical configuration. Field trials were performed using straw mass per metre and average layer thickness as evaluation metrics. Single- and multi-factor experiments combined with response surface methodology yielded optimal parameters: conveyor shaft speed of 230 r/min, crankshaft speed of 227 r/min, and a third-stage tooth height of 0.03 m. Field tests in desert environments confirmed straw output of 0.2–0.4 kg/m, layer thickness of 2–3 cm, burial depth of 14.3–19.5 cm, and exposed height of 19.8–39.5 cm. Results meet quality specifications for barrier construction, demonstrating the machine’s strong applicability and potential for engineering deployment in desertification control. Full article

Numerical simulation has played a crucial role in modeling the behavior of natural gas hydrate (NGH). However, the existing numerical simulators worldwide have exhibited limitations in functionality, convergence, and computational efficiency. In this study, we present a novel numerical simulator, GPSFlow/Hydrate, for modeling the behavior of hydrate-bearing geologic systems and for addressing the limitations in the existing simulators. It is capable of simulating multiphase and multicomponent flow in hydrate-bearing subsurface reservoirs under ambient conditions. The simulator incorporates multiple mass components, various phases, as well as heat transfer, and sand is treated as an independent non-Newtonian flow and modeled as a Bingham fluid. The CH₄ or binary/ternary gas hydrate dissociation or formation, phase changes, and corresponding thermal effects are fully accounted for, as well as various hydrate formation and dissociation mechanisms, such as depressurization, thermal stimulation, and sand flow behavior. In terms of computation, the simulator utilizes a domain decomposition technology to achieve hybrid parallel computing through the use of distributed memory and shared memory. The verification of the GPSFlow/Hydrate simulator are evaluated through two 1D simulation cases, a sand flow simulation case, and five 3D gas production cases. A comparison of the 1D cases with various numerical simulators demonstrated the reliability of GPSFlow/Hydrate, while its application in modeling the sand flow further highlighted its capability to address the challenges of gas hydrate exploitation and its potential for broader practical use. Several successful 3D gas hydrate reservoir simulation cases, based on parameters from the Shenhu region of the South China Sea, revealed the correlation of initial hydrate saturation and reservoir condition with hydrate decomposition and gas production performance. Furthermore, multithread parallel computing achieved a 2–4-fold increase in efficiency over single-thread approaches, ensuring accurate solutions for complex physical processes and large-scale grids. Overall, the development of GPSFlow/Hydrate constitutes a significant scientific contribution to understanding gas hydrate formation and decomposition mechanisms, as well as to advancing multicomponent flow migration modeling and gas hydrate resource development. Full article

The widespread application of granite manufactured sand (GS) concrete in pavement engineering is limited by issues such as suboptimal particle size distribution and an unclear optimal rock powder content. Furthermore, research on the long-term evolution of the skid resistance characteristics of GS concrete remains relatively scarce. This knowledge gap makes it difficult to accurately assess the skid resistance performance of GS concrete in practical engineering applications, thereby compromising traffic safety. To address this research gap, this study utilized a self-developed indoor abrasion tester for pavement concrete to assess the skid resistance of GS concrete. Three-dimensional laser scanning was employed to acquire the concrete’s surface texture parameters. Using the friction coefficient and texture parameters as skid resistance evaluation indicators, and combining these with changes in the concrete’s surface morphology, the study explores how effective sand content, stone powder content, and fine aggregate lithology affect the long-term skid resistance of GS concrete pavements and reveals the evolution trends of their long-term skid resistance. Research results show that as the number of wear cycles increases, low and high effective sand content affect the surface friction coefficient of specimens in opposite ways. Specimens with 95% effective sand content exhibit superior skid resistance. Stone powder content influences the friction coefficient in three distinct variation patterns, showing no clear overall trend. Nevertheless, specimens with 5% stone powder content demonstrate better skid resistance. Among different fine aggregate lithologies, GS yields a higher friction coefficient than river sand (RS), while limestone manufactured sand (LS) shows significant friction coefficient fluctuations across different wear cycles. Adding stone powder substantially enhances mortar strength and delays groove collapse edge formation. Moreover, higher effective sand content and proper stone powder content mitigate bleeding, thereby improving mortar performance. Full article

Cilantro (Coriandrum sativum L.) is a popular annual culinary herb grown for its leaves or seeds. With the increase in hydroponic herb production in controlled environments, a need exists for leaf tissue nutrient standards specific to this production system. The objective of this study was to develop comprehensive foliar mineral nutrient interpretation ranges for greenhouse-grown cilantro. Cilantro plants were grown in a hydroponic sand culture system to induce and document nutritional disorders. Plants were supplied with a modified Hoagland’s solution, which was adjusted to individually add or omit one nutrient per treatment while holding all others constant. Deficiency and toxicity symptoms were photographed, after which the plant tissue was collected to determine plant dry weight and critical tissue nutrient concentrations. Nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), boron (B), iron (Fe), and zinc (Zn) deficiencies, as well as B toxicity, were induced. Deficiencies of copper (Cu), manganese (Mn), and molybdenum (Mo) were not observed during the experiment. Additional foliar tissue analysis data (n = 463) were compiled to create nutrient interpretation ranges for 12 essential elements based on a hybrid meta-analysis Sufficiency Range Approach (SRA). This approach defines ranges for deficient, low, sufficient, high, and excessive values. For each element, the optimal distribution was selected according to the lowest Bayesian Information Criterion (BIC) value. A Normal distribution best represented K and S. A Gamma distribution best represented P, Ca, Mn, and Mo, whereas a Weibull distribution best represented N, Mg, B, Cu, Fe, and Zn. These interpretation ranges, along with descriptions of typical symptomology and critical tissue nutrient concentrations, provide useful tools for both diagnosing nutritional disorders and interpreting foliar nutrient analysis results of greenhouse-grown cilantro. Full article

The present study applied a GIS-based methodology for assessing soil diversity in a protected mountain area of Italy. Using QGIS, morphological (i.e., altitude and slope), lithological, climatic, and land use layers were intersected to delineate 16 land units (LUs), each representing relatively homogeneous conditions for soil formation, according to Jenny’s equation. To obtain the soil map units, a total of 112 soil profiles were analyzed, including 79 from previous studies and 33 that were newly excavated during 2023–2024 to fill gaps in underrepresented LU types. Most soils were classified as Inceptisols/Cambisols, occurring in both Dystric and Eutric variants, mainly in relation to lithology (i.e., arenaceous or pelitic facies). Alfisols, Umbrisols, and hydromorphic soils were also identified. The physicochemical properties showed marked variability among LUs, with sand content ranging from 39 to 798 g kg⁻¹, pH from 4.4 to 7.9, and organic carbon content from 1.6 to 6.1%. This LU-based framework allowed efficient field sampling, if compared to grid-based surveys, while retaining information on fine-scale pedodiversity. No quantitative accuracy assessment (e.g., boundary precision, internal homogeneity metrics) was conducted, even if the spatial coherence of the delineated LUs was supported by the distribution of soil profiles, which provided empirical validation of the LU framework. Full article

This study investigates the internal structure and lithologic variability of slope deposits in a small catchment in the Polish Outer Carpathians using pedological methods supported by geochemical analyses and Electrical Resistivity Tomography (ERT). It addresses the occurrence of lithologic discontinuities in the soils of flysch-dominated mountain areas. Diagnostic criteria from the WRB system—based on particle-size distribution and the content and lithology of coarse fragments—were applied to identify lithologic discontinuities, complemented by computation of sand and silt separates on a clay-free basis. Geochemical analyses and ERT were then used to assess their likely origin. Three major vertical sections were distinguished, separated by discontinuities: an uppermost unit consisting of aeolian material mixed with solifluctional deposits; a middle unit dominated by solifluctional materials; and a lowermost unit composed of colluvial deposits. The study confirms the utility of ERT in detecting subsurface differentiation of stratified slope sediments and provides a model for interpreting pedosedimentary sequences in Carpathian low-mountain environments. Full article

The Mindong–Changchunling region is situated in the central portion of the Songliao Basin, Northeast China. The primary target stratum in this area is the Fuyu Oil Layer of the Lower Cretaceous Quantou 4 Member. This reservoir is predominantly composed of fine sandstone and siltstone, with minor interbedded medium sandstone. Variations in provenance, sedimentation, and diagenesis are identified as the main controlling factors for the distribution of high-quality reservoirs in the Mindong–Changchunling region. The sand body distribution in the Changchunling area is influenced by the eastern near-source provenance. The reservoir properties of these sand bodies are impacted by the poor sorting and high mud content typical of near-source delta sand bodies. Nonetheless, reservoir quality is enhanced by late-stage uplift and surface water dissolution-leaching. In contrast, sand body distribution in the Mindong area is governed by the southwestern far-source provenance. Far-source delta sand bodies are characterized by better sorting but high mud content, with their reservoir properties primarily impaired by carbonate cementation. During the early-middle diagenetic stage, feldspar dissolution by organic acids improves sand body reservoir quality. Due to variations in sedimentation and diagenesis, the following three favorable reservoir zones with distinct genetic types have developed in the Mindong–Changchunling area: the Chang107–Chang104–Chang52 well block, the Fu155–Fu161–Fu157 well block, and the Min103–Min31 well block. Full article

Synchronous grouting slurry is widely used in shield tunnel construction to fill the gaps between stratum and shield tail segments. However, as grout is nearly liquid in the initial stages, the tunnel lining segments recently separated from the shield tail are easily affected by the upward buoyancy generated by grout, causing issues such as longitudinal misalignment and opening of ring joints. Therefore, studying the upward buoyancy characteristics of synchronous grout is crucial. In this study, floating characterisation parameters of grout were investigated using buoyancy model tests, orthogonal tests, and comprehensive tests. The floating characterisation parameters are affected by distribution ratio and types of each grout component. The relationship between the floating characterisation parameters of grout and buoyancy was established. The results show that density, flow index, and shear strength can be used as the floating characterisation parameters. Binder–sand and water–binder ratios have the largest impact on the density. The bentonite–water ratio exerts a primary influence on the flow index, while the water–binder ratio contributes a secondary effect. In addition, bentonite–water and binder–sand ratios have the greatest effect on the shear strength. Furthermore, the particle size of sand and type of bentonite considerably influence the flow index and shear strength. A high-shear grout using well-graded fine sand and a high mesh of sodium bentonite was considered in this study. When the content of bentonite exceeds 7% (P2.2), Archimedes’ law is not applicable for calculating the upward buoyancy of grout. Buoyancy supply rate exhibits gradual enhancement with flow index elevation, yet with diminishing growth rates. Full article

The conventional recycling processes for waste sand with inorganic binder (WSIB) in aluminum alloy casting involve washing, heat treatment, and mechanical grinding. However, this process is complex and inefficient for removing the residual binder on the surface of WSIB. This study proposes a simplified and effective recycling process using ultrasound treatment to more efficiently remove residual binder on the surface of WSIB. To evaluate its effectiveness, we characterized ultrasonically recycled sand (URS), conventionally recycled sand (CRS), and virgin sand (VS). The evaluation consisted of the following three steps: (1) characteristics of sand, such as residual binder content, particle size distribution, surface morphology, and specific surface area; (2) measuring the properties of sand cores, including bending strength and the volume of gas evolved during the pouring of A356 Al melts; and (3) measurement of porosity level at the interface between the sand core and A356 Al castings. These results indicate that the ultrasonic recycling process can achieve a technically efficient and simplified recycling process for WSIB. Full article

Tests during methane hydrate (MH) production in Japan have shown that excessive water production is a primary challenge in MH development. It can lead to sand production, inhibit effective reservoir depressurization, and hinder gas production. This study investigated the ability of a reactive grout, produced by the in situ reaction of CO₂ with sodium silicate (SS), to inhibit water generation from unconsolidated sand layers by forming a water-blocking gel barrier. The performance of this grout was evaluated through laboratory experiments using silica sand as a porous medium. Under controlled conditions, diluted SS and CO₂ were sequentially injected. The injection and gelation processes were monitored in real time using CT scanning, and SEM was employed to analyze the microstructure of the reaction products. The results indicated that SS exhibited piston-like flow, with elevated concentrations increasing viscosity and promoting more uniform injection. CO₂ injection resulted in successful in situ gel formation. A homogeneous gel distribution decreased permeability by ~98% when the SS concentration was 25 wt%. However, at 50 wt%, rapid localized gelation caused preferential flow paths and reduced sealing efficiency. These findings highlight the potential of CO₂ reactive grouting for water management in MH exploitation and the importance of optimizing injection parameters. Full article

Particulate matter (PM), a complex mixture of solid particles and liquid droplets, originates from both natural sources, such as sand, pollen, and marine salts, and anthropogenic activities, including vehicle emissions and industrial processes. While PM itself is not inherently toxic in all its forms, it often acts as a carrier of xenobiotic toxicants, such as heavy metals and organic pollutants, which adhere to its surface. This combination can result in synergistic toxic effects, significantly enhancing the potential harm to biological systems. Due to its small size and composition, PM can penetrate deep into the respiratory tract, acting as a physical “shuttle” that facilitates the distribution and bioavailability of toxic substances to distant organs. The omnipresence of PM in the environment leads to unavoidable and constant exposure, contributing to increased morbidity and mortality rates, particularly among vulnerable populations like the elderly, children, and individuals with pre-existing health conditions. This exposure also imposes a substantial financial burden on healthcare systems, as treating PM-related illnesses requires significant medical resources and leads to higher healthcare costs. Addressing these challenges necessitates effective mitigation strategies, including reducing PM exposure, improving air quality, and exploring novel approaches such as AI-based exposure prediction and nutritional interventions to protect public health and minimize the adverse effects of PM pollution. Full article