Erosion Area Research Articles

Exploring landscape ecological risk with human activity intensity and correlation in the Kuye River Basin

IntroductionThe Kuye River Basin, a typical erosion area of the Loess Plateau region with the second largest tributary of the Yellow River Basin, faces significant environmental challenges and intense human activities. Balancing environmental sustainability and economic development in this region is urgent.MethodsTherefore, this study takes this basin as the object and evaluates the landscape ecological risk and human activity intensity from 2000 to 2022 based on land use/land cover, population distribution and nighttime lighting data. And a geographically weighted regression model was used to reveal the correlation between the two.Results and discussionResults showed that the average landscape ecological risk index in 2000, 2015, and 2022 were 9.01×10-4, 5.61×10-4, and 7.40×10-4, respectively. This shows that the overall landscape ecological risk index is low in the first 15 years and then gradually increases over time. Cultivated land, grassland and construction land are the main landscapes, the expansion of 7.95 times construction land is a key factor in the intensification of human activities, mainly concentrated in the northwest, followed by a gradual expansion towards the south-east, and likewise the landscape ecological risks follow the same trend. Medium to high intensity human activities exacerbate landscape ecological risks, with a significant positive correlation, while low intensity human activities cause little damage to landscape ecology. To achieve sustainability, it is necessary to effectively control construction land and improve land use structure. Then, in the planning work, priority will be given to the northwest region with high human activity intensity and high landscape ecological risks, and the governance direction will gradually shift to the southeast region. These findings provide empirical evidence to support decision-making and underscore the need for comprehensive strategies to mitigate landscape ecological risks and promote sustainable development in the Kuye River Basin.

Effect of particle impact on spatial and temporal erosion characteristics of turboshaft engine compressor

When turboshaft engines operate in dusty environments, particulate matter erodes the compressor blades, which may leads to structural damage and presents a severe threat to the operational reliability and safety of helicopters. The aim of this study is to determine the erosion characteristics of compressor blades and how it changes with time. Particle velocimetry and erosive experiments were conducted to obtain the SiO2 particle velocity and the erosion rate of the Ti-6Al-4V titanium alloy. Based on the measured data, the parameters of the Tabakoff erosion model have been refined, which is critical for establishing a transient erosion model for the 1.5-stage compressor of a turboshaft engine that accounts for the effect of particle erosion time. Simulation results show that the motion behaviour of particles exhibits changing patterns at different time intervals, which leads to variations in the erosion area and erosion rate of the compressor. The erosion area and rate on blades increase nonlinearly with time. In some locations, when erosion time increases, the erosion area and erosion rate also increase. While, in other locations, the erosion area and erosion rate hardly change with time. The maximum erosion rates increased by 27.3%, 28.6%, and 87.2% for the guide blades, 42.9%, 69.6%, and 84.0% for the rotor blades, and 69.0%, 103.6%, and 142.8% for the stator blades at 0.50s, 0.75s, and 1.00s, respectively, in comparison to 0.25s.

Evaluation of dyspepsia symptom severity in pediatric patients: association with endoscopic and pathological findings

Aims: There is diagnostic difficulty in distinguishing between organic and functional causes of dyspepsia, which is characterized by a variety of gastrointestinal symptoms. This study aimed to evaluate the correlation between dyspeptic complaints, clinical symptoms, endoscopic findings, and pathology results in pediatric patients. Methods: A total of 159 children aged 8-17 years with dyspeptic complaints underwent upper gastrointestinal endoscopy (UGE). The Dyspepsia Symptom Severity Index (DSSI), comprising three parts (dysmotility-like, reflux-like, and ulcer-like symptoms) and 19 questions, was used to assess symptom severity. Endoscopic procedures were performed under general anesthesia, and biopsy samples were obtained. Results: The study included 159 patients with a median age of 15 years (ranging from 8 to 17 years). Among them, 29.1% were male (38) and 76.9% were female (121). DSSI scores were calculated for each subgroup and the total score. When assessing the relationship between chronic diseases and DSSI scores, no significant association was found (p=0.48). However, smoking showed a significant correlation with DSSI scores (p=0.01 for dysmotility-like, p=0.02 for reflux-like, and p<0.01 for ulcer-like symptoms). Gender differences were observed in DSSI scores, with girls exhibiting significantly higher median scores for dysmotility-like findings compared to boys (p=0.02). Endoscopy findings also correlated with DSSI scores, with significantly higher scores in patients with ulcers (p<0.01). Pathological findings such as esophagitis were found to have significant associations with reflux-like symptoms (p=0.04), and crypt hyperplasia was associated with ulcer-like symptoms (p=0.04) in patients with DSSI subgroup scores. However, no significant differences were found between pathology findings and dyspepsia severity, significant associations were observed between UGE findings (such as ulcers, pangastritis, erosional areas, and fragility) and ulcer-like symptoms. Conclusion: The study found significant links between dyspepsia severity and endoscopic results, stressing the need for reliable symptom scales for pediatric patients. It also highlights smoking as a factor in dyspepsia severity in children. Further research is needed to evaluate endoscopy's effectiveness in distinguishing between organic and functional dyspepsia. The study points out the limited understanding and consensus on diagnosing and managing dyspepsia in children, calling for the development of validated symptom scales and further research into cost-effective management strategies.

Gastric lesions associated with the infection of Anisakidae nematodes in a dwarf sperm whale Kogia sima (Owen, 1866) stranded in the north coast of Brazil

The present study aimed to describe gastric lesions associated with parasitism by different nematodes of the family Anisakidae in a stranded specimen of dwarf sperm whale (Kogia sima) on the northeast coast of the State of Pará, northern Brazil. Specimens of helminths and samples of stomach tissue were collected from a dwarf sperm whale, stranded on Humaitá beach, State of Pará, Brazil. Stomach showed areas of erosion and ulcers, with the mucosa covered by fibrinonecrotic material containing bacteria and inflammatory infiltrate predominantly comprising polymorphonuclear cells. Granulomas were also found in the submucosa, characterized by central areas of necrosis and hemorrhage, and cross sections of nematodes were observed. Fourth-stage larvae of the genus Pseudoterranova, two morphotypes of fourth-stage larvae of the genus Anisakis and adult specimens of Skrjabinisakis paggiae were morphologically identified. Molecular and phylogenetic analyzes confirmed the identity of the partial sequences of the cox2 mtDNA gene for adult specimens of S. paggiae. This study contributes to our understanding of the distribution of different of anisakids in K. sima and about the gastric lesions associated with these nematodes, in addition to expanding the knowledge about the occurrence of this aquatic mammal recorded for the first time in the northern region of Brazil.

The effect of surface flow conditions on WEPP interrill erodibilities

The Water Erosion Prediction Project erosion model (WEPP) was developed as an event-based more process-based replacement for Universal Soil Loss Equation (USLE) based models in predicting soil erosion as a guide to conserving soil in the USA. However, WEPP has not been shown to predict event soil losses for bare fallow USLE plots better than USLE-based models when stipulated input values have been used. To some extent, this problem can be attributed to the availability of more refined and site-specific input parameters for the USLE-based models. This is true with respect to WEPP’s capacity to model raindrop-driven erosion on USLE plots under natural rainfall. Stipulated values for WEPP interrill erodibilities in the USA were determined only for ridge side slopes but USLE-based models focus on the prediction of long-term average annual soil loss caused by both sheet and rill erosion on planar surfaces. The interrill erodibilities determined for ridge side slopes did not correlate well with those on adjacent flat surfaces sloping along the land slope under the same rainfall conditions. Surface flow conditions, particularly flow depth, differ between the short high gradient side slopes associated with ridges, and the lower gradient slopes in interrill and sheet erosion areas on USLE plots. Failure of WEPP to account for the influence of different flow conditions between ridged and flat areas on raindrop-driven erosion affects the veracity of WEPP to predict average annual soil loss on USLE plots under natural rainfall and the use of WEPP to act as a replacement for USLE based models as an aid to make land management decisions to conserver soil in the USA.

Research on controlling measures of snowdrifts around Arctic ground-based buildings through shape optimization

Elevated structures in the Arctic region have proven effective in mitigating surrounding snowdrifts by enhancing the airflow beneath, and serve as a preferred architectural form. However, ground-based buildings still occupy the dominant position due to the constraints posed by construction costs and foundation conditions. One of the effective measures to reduce and prevent snowdrifts around such buildings is to modify their aerodynamic shapes. Therefore, this research endeavors to explore measures for controlling snowdrifts around ground-based buildings through shape optimization. Initially, the predictive accuracy of a refined Mixture model for simulating snowdrifts around ground-based structures was checked against wind tunnel test results. Based on the validated numerical model and representative Arctic meteorological conditions, the snowdrift controlling effects by changing the overall and local building shapes were investigated separately. Overall, the snow reduction and prevention effects can be effectively achieved for ground-based buildings with smoother sidewalls, such as those featuring a circular plane. Conversely, for traditional rectangular ground-based buildings, a larger downwind aspect ratio and a more inclined windward surface can significantly diminish peak snow depth. Additionally, the measures by adding windward side chamfering can effectively manage the locations of snow erosion areas, thereby enabling flexible placement of entrances and exits.

Vegetation Density Mapping of Urban Solid Waste Landfill Coverage Using Vegetation Indexes Obtained with UAV

Objective: The objective of this study is to map the vegetation cover of a municipal solid waste landfill using high-resolution vegetation index images obtained with UAV, as a tool for geotechnical monitoring. Theoretical Framework: The theoretical framework describes the state of the art of vegetation indexes, starting from the first proposal of NVDI by Rouse et al. (1973), through to the NDWI by McFeeters (1996). Additionally, it presents the method of representing radiometric variables, considering that these indexes operate based on the ratio between spectral bands, which are displayed within intervals ranging from -1 to +1. Method: The study used a UAV equipped with MAPIR multispectral camera to capture images of the landfill. NDVI and NDWI indexes were applied to assess vegetation health and coverage. Field control points determined with GNSS-RTK, along with protogrametry software, ensured mapping accuracy, creating high-resolution orhomosaics for monitoring and determining vegetation indexes. Results and Discussion: The results indicate variation in vegetation cover, revealing areas of exposed soil ang vegetation at different stages of vigor, from senescence to full growth. The NDVI and NDWI indexes highlighted regions with water stress and soil exposure, demonstrating the effectiveness of the method in environmental and geotechnical monitoring. Conclusions: It is concluded that the use of UAVs and vegetation indexes are effective for monitoring vegetation health and landfill stability, enanbling the identification of erosion areas and the need for vegetation cover restoration.

Erodibility Prioritization and Mapping of a Mid Himalayan Watershed Using Technique of Order Preference by Similarity to Ideal Solution (TOPSIS)

The productivity of soils is drastically affected owing to soil erosion in human activities in the decline of the Western Nayar watershed situated in the Pauri district of Uttarakhand. Therefore, evaluation of these erodible areas is of utmost importance so that the preventive measures can be taken accordingly. It assessed the sub-basins in the basin using morphometric parameters and several multi- criteria decision-making models, such as Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), Utilizing Advanced Space Thermal Emission Radiometer (ASTER) data and a 30 m Digital Elevation Model (DEM), morphometric parameters were extracted and analyzed. To test the MCDM methods, percent and intensity of change indices were adopted. The ranking results were such that sub-watershed 2 was ranked at top as the most susceptible to erosion for TOPSIS model,In general, the morphometric parameters were effective for identifying erosion-prone areas.

Detection of tree destruction induced by heavy rainfall in the afforested loess catchment of China

Rainstorm events are becoming increasingly frequent due to the impacts of global warming, which results in widespread erosion disasters and related tree destruction. However, previous corresponding studies of forest damage have focused on typhoons or wildfires, ignoring the increasing risk of rainstorm erosion-induced tree destruction. It is unclear what scale of tree destruction can be caused by heavy rainfall. In this study, we used a tree segmentation method based on airborne light detection and ranging (LiDAR) technology to accurately quantify the tree destruction during heavy rainfall in a representative afforested catchment on the Chinese Loess Plateau. Additionally, topographic changes were calculated using pre- and post-heavy rainfall LiDAR datasets, and tree destruction was assessed by combining terrain information and tree structural parameters. The results showed that 3253 trees in the catchment (0.9 km2) were destroyed due to rainstorm erosion, among which 2845 trees were located on gully slope landform, accounting for 87.4 % of all destroyed trees. Tree destruction on steep gully slope (slope: 45.5°-50.5°) was mainly induced by rainstorm erosion, while that on both sides of the gully bed (altitude: 1137 m-1147 m) was mainly induced by sediment deposition. In the catchment, the deposition area that resulted in tree destruction (21265 m2) was greater than the erosion area (20020 m2). However, the damage caused by erosion was more destructive than that caused by deposition. There was a significant linear relationship between tree structural parameters and terrain in the forestland catchment. Our study provides a reference methodology for studies of forest damage due to extreme weather events worldwide, and has significant implications for ecosystem management and reforestation in the context of global change.

Treatment of mycotic rhinitis caused by aspergillus fumigatus in a quarter horse mare using topical clotrimazole and oral potassium iodide.

Fungal rhinitis in horses is rare, although severe, due to the progressive nasal obstruction. Aspergillus is one of the fungi most often involved in these cases. A 7-year-old Quarter Horse mare weighing 325kg was admitted with a history of recurrent nasal discharge and bleeding, foul smell, reluctance to exercise, and abortion. Laboratory and imaging examinations revealed eosinophilia, scarring and erosion areas in the nasal mucosa, purulent and bloody secretions, and remarkable yellowish plaques. Histopathological examination revealed fungal rhinitis and bacterial culture revealed the presence of β-hemolytic Streptococcus and Staphylococcus sp. Fungal culture and molecular diagnosis confirmed Aspergillus fumigatus as the etiological agent. A tracheostomy was necessary due to the patient's dyspnea. For the treatment, topical application of clotrimazole ointment was carried out in the rostral portion of the nasal cavity once a day and in the caudal portion of the nasal cavity, endoscopic guided every 48h. In the fifth endoscopy-guided application, a significant improvement was noticed; however, the animal exhibited a hypersensitivity reaction, and the treatment was discontinued. Thus, potassium iodide therapy was initiated (67mg/kg, PO, SID, 14 days). The patient demonstrated favorable clinical improvement, achieved resolution of the fungal infection, and was discharged after 25 days of hospitalization. Topical clotrimazole demonstrated a probable efficacy as a standalone treatment, although its use had to be prematurely discontinued due to the emergence of a hypersensitivity reaction. The combination of clotrimazole and potassium iodide effectively treated fungal rhinitis in a shorter time than previously reported. This report provides useful guidance for other cases of fungal rhinitis, although further studies are needed.

Analysis of chemical and morphological properties of root dentine treated with a single multifunctional endodontic irrigant solution.

The aim was to evaluate the chemical, morphological aspects and microhardness of root dentin after treatment with Triton™ solution. Twenty blocks of root dentin were distributed in two groups (n = 10): Control (C) (2.5% NaOCl+17% EDTA+2.5% NaOCl) and Triton™ solution (T). Morphological analysis was performed before and after treatments with confocal laser microscopy. Chemical composition and microhardness were analysed after the treatments using Raman spectroscopy and Knoop microhardness. Results were submitted to Student's t-test and Mann-Whitney test (p < 0.05). The C group had greater tubule number, area and perimeter (p < 0.001), besides a regular surface, while T showed an irregular surface with cracks and erosions, lower organic content intensity (p < 0.001) and higher inorganic/organic ratio (p = 0.003) than C, which had higher microhardness than T (p = 0.003). Triton™ exposed a lower number, area and perimeter of dentinal tubules, with cracks and erosions in root dentin. It also showed significant chemical alterations in the organic content, reducing it, resulting in lower microhardness.

Do penguins care about their neighborhood? Population implications of bioerosion in Magellanic penguin, Spheniscus magellanicus, at Martillo Island, Beagle Channel, Argentina.

Intrinsic and extrinsic factors, such as bioerosion at nesting sites, regulate population dynamics and are relevant for the long-term conservation of penguins. Colony trends (between 2004-2022) were studied in a Magellanic penguin colony on Martillo Island, Beagle Channel, Argentina and compared between zones with contrasting degrees of erosion (high, medium, low). Individuals from each zone were characterized for foraging ecology, stress, and reproductive performance during the 2017-2018 breeding season to better understand the colony dynamics. Changes in nest abundance varied in magnitude between nesting zones with different characteristics of occupation time, density and erosion. Declines in nest abundance in the densest, most eroded and longest occupied zone suggests that environmental degradation may be limiting the colony's carrying capacity. A higher percentage of late breeders (probably younger breeders) occupied the less eroded and more recently occupied zone. Foraging, breeding and stress barely differed between zones. New individuals recruiting into the breeding colony select less-eroded zones, either to reduce competition for nests or to avoid other effects of erosion and high-density areas. If this is the mechanism behind the shift in numbers throughout the island, we expect the island to be progressively occupied to the west. If competition or other density dependent factors are at play, a time will come when the vacant east side will begin to be recolonized by younger individuals. However, if erosion or other long-term effects spread throughout the island, recolonization may not occur and the colony may ultimately be abandoned as individuals search for new breeding grounds. Erosion at the breeding site may be a key factor in regional population trends of this burrow nesting species, by following an extinction / colonization of new sites process.

Empirical and Machine Learning Models for Soil Erosion Risk Assessment: A Case Study of Tsageri Municipality, Georgia

Soil erosion caused by water is one of the most common causes of land degradation worldwide. Within framework of this research soil erosion risk in Tsageri municipality, Georgia was evaluated using Revised Universal Soil Loss Equation (RUSLE) and a machine learning-based Random Forest (RF) model. Open access digital datasets and field observations collected in 2023-2024, which included visually identified erosion areas and GPS-recorded data on the presence or absence of erosion, were utilized in modeling process. Data processing and modeling conducted using ArcGIS Pro 3.0 and RStudio software. According to RUSLE results, 39.7% of the study area falls under the very low erosion risk zone, and 20.7% is in the very high risk zone. The RF model results indicated that 16.5% of the territory is under very low risk of erosion and 13.9% - very high risk. It was observed that RUSLE model tends to overestimate erosion rates on steep, forested slopes, while the RF model, by incorporating additional variables, provided more accurate prediction. These findings suggest that combining RUSLE with machine learning improves soil erosion risk assessment, particularly in complex landscapes such as in Tsageri municipality. Future researche should focus on testing additional variables to refine the modeling process further and enhance predictions. The generated digital thematic maps offer valuable insights for understanding the spatial dynamics of soil erosion within the study area, analyzing the factors driving the process and developing effective mitigation strategies.

Numerical Prediction of Solid Particle Erosion in Jet Pumps Based on a Calibrated Model

Jet pumps are widely used in petrochemical processes, nuclear cooling, and wastewater treatment due to their simple structure, high reliability, and stable performance under extreme conditions. However, when transporting solid-laden two-phase flows, they face severe erosion problems, leading to reduced efficiency, malfunctions, or even failure. Therefore, optimizing jet pump performance and extending its service life is crucial. In this study, an experimental platform was established to conduct experiments on wall erosion in jet pumps. The CFD-DEM method was used to simulate the solid–liquid two-phase flow in the jet pump, comparing six erosion models for predicting erosion rates. The Grey Wolf Optimization algorithm was applied to calibrate model coefficients. The results indicate that the Neilson erosion model shows the best consistency with the experimental results. The inlet flow rate significantly influenced the erosion rates, while the flow rate ratio had a smaller effect. The particle concentration exhibited a nonlinear relationship with erosion, with diminishing impact beyond a certain threshold. As the factors varied, the erosion distribution tended to be uniform, but high erosion areas remained locally concentrated, indicating intensified localized erosion.

Estimation of soil loss and sediment yield by using the modified RUSLE model in the Indus River basin, including the quantification of error and uncertainty in remote-sensing images

Context Indus River is the cradle of Pakistani lifeline, and its lower reaches are prone to soil loss owing to bank erosion. Aims The aim was to investigate the sediment yield in the Lower Indus River Basin (LIRB), while addressing challenges related to error or uncertainty in remote-sensing data. Methods We employed a modified revised universal soil loss equation (RUSLE) model, integrating high-resolution digital elevation model (DEM) and calibrated Climate Hazards Group InfraRed Precipitation with station data (CHIRPS). Additional data layers, including land use, soil and cropping data, were also utilised. Key results The extent of actual soil erosion ranges from minimum to maximum erosion; 38.9% area lies in the range &gt;50 Mg ha‒1 year‒1, whereas 23.2% area lies in the range of 0–10 Mg ha‒1 year‒1, and 18.1% area lies in the range of 10–20 Mg ha‒1 year‒1. Conclusions The study identifies critical erosion areas and tackles uncertainties in remote-sensing data. The spatial analysis showed that higher distribution sediment erosion along the channel flow direction from the northern part of LIRB to the Arabian Sea. Implications The findings have provided critical information for policymakers and water managers to implement effective measures to reduce erosion, maintain soil integrity and promote the sustainability of the Indus River system.

The Effect of In Situ Laser-Assisted Plasma Spraying on the Plasma Etching Resistance of Yttrium Oxide Coating

In recent years, yttrium oxide coatings prepared by atmospheric plasma spraying (APS) have been employed extensively in semiconductor processing equipment. Meanwhile, defects in yttrium oxide coating, such as unmelted particles and pores, reduce the etching resistance of the coating. In this work, two yttrium oxide coatings were prepared by in situ laser-assisted plasma spraying (LAPS) coupled with a 500 W and 600 W laser for comparison with a coating prepared by APS, and the effects of the laser on the coating properties were investigated. The results show that the surface roughness was reduced by 25.7% (500 W) and 25.3% (600 W) and the porosity was reduced by 52.3% (500 W) and 36.9% (600 W) after laser coupling. After being etched by CF4/CHF3 for a long time, it was observed from SEM, EDS and XPS analyses that the intensity ratios of the Y-F bonds in the coating were 1 (APS):1.3 (LAPS+500W):1.1 (LAPS+600W), which indicated that the LAPS+500W coating had a thicker fluorination layer. It was also observed that the fluorination layer at the defect was first eroded; then, the erosion area gradually spread to the surrounding area, and finally, the fluorination layer was etched. This indicated that the defects had a significant impact on the etching resistance. Consequently, the LAPS+500W coating with fewer defects and a thicker fluorination layer showed the lowest etching rate. Therefore, in situ laser-assisted plasma spraying coupled with an appropriate laser power is an effective method to improve the performance of yttrium oxide coatings.

Remote sensing image segmentation of gully erosion in a typical black soil area in Northeast China based on improved DeepLabV3+ model

Gully erosion, a cause of soil degradation and reduced crop yields is widespread in the diffuse river and hillock regions of Northeast China. The surface conditions in gully erosion areas are complex, and manual extraction methods are inefficient, hindering gully erosion monitoring progress. Accurate extraction of gullies is essential for effective environmental monitoring and management. In this study, we propose an improved deep learning network, named DD-DA (the DeepLabV3+ deep network with dual attention mechanism), for automatic and precise gully erosion extraction from 2 m resolution Gaofen-6 remote sensing images from the Heshan Farm area. The DD-DA model builds upon the DeepLabV3+ network architecture with targeted optimizations. Firstly, ResNet50 replaces the original backbone network of DeepLabV3+, enhancing feature extraction capabilities. Second, the Convolutional Block Attention Module (CBAM) integrates spatial and channel attention, improving the model's capacity to capture the shape and texture features of gully erosion. Finally, the Dice loss function is adopted to address the limitations of the traditional cross-entropy loss function, particularly in handling unbalanced datasets. To promote deep learning applications in gully erosion monitoring in Northeast China, a gully erosion dataset was constructed. Experiments on gully erosion datasets show that DD-DA can achieve high Mean Intersection over Union (MIoU) (79.21 %), Pixel Accuracy (96.17 %), Recall (87.66 %), F1-Score (86.48 %), and Precision (86.08 %) simultaneously, which significantly outperform traditional image processing methods and recently deep learning networks. Overall, DD-DA efficiently and accurately segment gully erosion in agricultural fields, significantly improving the extraction of gully erosion features from high-resolution remote sensing images, particularly in the black soil regions of northeastern China. Meanwhile, this study offers a solution for the rapid monitoring of gully erosion and provides substantial technical support for extracting other land degradation features, such as soil salinization and desertification.

Hot metal erosion behavior of Al2O3-SiC-SiO2-C castable hot surface in blast furnace hearth

An ASSC-type cast-type blast furnace with a vertical stage of about 2500 m3 was dissected in present study. There is an iron penetration erosion area with a thickness of about 170 mm in the hot side castable on the hearth sidewall. Iron penetration erosion is concentrated on the hottest surface of the castable. Along the radial direction, from the hot to cold surface, the erosion is different, divided into a metamorphic layer, an erosion layer, and a transition layer. The phase composition and microstructure of the hot surface of the castable after service were studied by chemical analysis and SEM-EDS. The penetration model was applied to calculate the critical pore size of molten iron penetrating the castable, and the universality of molten iron penetrating the castable was proved. Combined with the thermodynamic calculation results, it is shown that in the hearth environment, the molten iron penetrating the castable will react with SiO2 and C to form ferrosilicon and CO gas. CO reacts with SiC and Al2O3 in the castable, and the products are mullite phase and C phase. The two reactions occur at the same time, resulting in the continuous erosion of the aggregate silicon-containing phase of the castable. The Al2O3 in the castable will gradually disintegrate under the erosion of high-temperature molten iron and periodic thermal shock and finally form the erosion phenomenon in the hot surface area of the castable.

Spatiotemporal patterns and driving factors of soil protection in the wind-water erosion area of Chinese Loess Plateau

Spatiotemporal patterns and driving factors of soil protection in the wind-water erosion area of Chinese Loess Plateau

An improved Eulerian-Lagrangian method combined with ductile material model for cavitation erosion assessment

Abstract Cavitation erosion in hydraulic machinery constitutes a multifaceted, instantaneous physicochemical process resulting in material wear and decreased efficiency. This paper employs an enhanced Eulerian-Lagrangian method to evaluate cavitation erosion. The method captures erosive impact loads released by the non-spherical collapse of near-wall bubbles and integrates them with a one-dimensional ductile material mode, a capability lacking in traditional homogeneous mixture methods. A classic axisymmetric nozzle test case is conducted under four different cavitation numbers (s=0.8, 0.9, 1.09, and 1.6) to validate the reliability of the new approach. Qualitative and quantitative analysis demonstrates that the impact load distribution on the lower and upper walls aligns with experimental measurements. Compared with reference works, the new method accurately predicts the maximum wear position and yields a narrower erosion area closer to the experimental data. Moreover, the relative error of the minimum incubation time at s=0.9 on the lower wall calculated by the new method is 4.67%, and the relative error of the maximum wear rate is 36.6%. This method is pivotal for further studying how various materials respond to cavitation wear. Further analysis reveals that material response patterns are similar under cavitation erosion conditions at s=0.8, 0.9, and 1.09. In contrast, the material surface wear rate is reduced by 46.7%, and the incubation time nearly triples at s=1.6.