Degree Of Erosion Research Articles

Predictive modeling of diverse factors impacting regional soil erosion degree with machine learning

Predictive modeling of diverse factors impacting regional soil erosion degree with machine learning

Effect of Nb Doping on the Electrical Contact Properties of AgNi Contact Materials

AgNi contact materials have received widespread attention with the acceleration of the process of replacing AgCdO contact materials. However, the practical applications of AgNi contact materials are limited due to its disadvantage of poor resistance to melting welding. Firstly, following the first principles of the density functional theory, we simulated and tested an interfacial model of AgNi doped with varying amounts of Nb. Next, we fabricated AgNi electrical contact materials. Subsequently, we conducted electrical contact tests. Finally, the impact of Nb doping on the arc erosion behavior of AgNi electrical contact materials was analyzed. The results indicate that, with an increase in Nb doping content, the electrical contact performance and the degree of arc erosion exhibit a trend of initially decreasing and then increasing, which aligns with the simulation results. The mean values of arc energy, arc duration, and welding force for the material doped with 4.55% Nb were 181.02 mJ, 9.43 mS, and 38.45 cN, respectively. Moreover, the anode is more responsive to changes in Nb content compared to the cathode. The introduction of Nb enhances the viscosity of the molten pool in the AgNi electrical contact. Furthermore, the mechanisms of grain boundary strengthening and solid solution strengthening by Nb improve the weld performance resistance of the contact.

ИСПОЛЬЗОВАНИЕ ПЛОДОРОДНОГО СЛОЯ ПОЧВЫ ДЛЯ РЕКУЛЬТИВАЦИИ

The purpose of research is to study ways to use fertile soil layer for reclamation. Objectives: to study the requirements for the reclamation of lands disturbed during underground mining; to study ways to store fertile soil layer; to study methods of applying topsoil and potentially fertile rocks. The objects of this study were scientific publications and patents of Russian and foreign authors concerning the negative impact of the coal mining industry and ways to minimize this impact. Land reclamation includes preparatory, technical and biological stages. The preparatory stage includes surveying the territories and determining directions for reclamation. The technical stage includes the process of removing the fertile layer and forming a reclamation layer. The biological stage includes sowing herbs and planting trees and shrubs. The fertile layer of soil can be stored in piles for 20 years. Areas unsuitable for agriculture or unproductive land should be allocated for the piles, where flooding, salinization and pollution by industrial waste, solid objects, stone, crushed stone, pebbles, and construction waste are excluded. The application of a fertile or potentially fertile soil layer involves the use of hydraulic transport or other transportation methods with attachments that ensure the application of a soil layer of a given thickness without leveling work. The thickness of the applied fertile layer is differentiated depending on the degree of soil erosion. In order to return disturbed lands for use in various sectors of the national economy and eliminate their impact on the environment, it is necessary to carry out reclamation work by developing projects for reclamation work as part of land dumps for mining enterprises.

Quantification of soil erosion and sediment yield using the RUSLE model in Boyo watershed, central Rift Valley Basin of Ethiopia

Changes in land use and land cover (LULC) are becoming recognized as critical to sustainability research, particularly in the context of changing landscapes. Soil erosion is one of the most important environmental challenges today, particularly in developing countries like Ethiopia. The objective of this study was evaluating the dynamics of soil loss, quantifying sediment yield, and detecting soil erosion hotspot fields in the Boyo watershed. To quantify the soil erosion risks, the Revised Universal Soil Loss Equation (RUSLE) model was used combined with remote sensing (RS) and geographic information system (GIS) technology, with land use/land cover, rainfall, soil, and management approaches as input variables. The sediment yield was estimated using the sediment delivery ratio (SDR) method. In contrast to a loss in forest land (1.7 %), water bodies (3.0 %), wetlands (1.5 %), and grassland (1.7 %), the analysis of LULC change (1991–2020) showed a yearly increase in the area of cultivated land (1.4 %), built-up land (0.8 %), and bare land (3.5 %). In 1991, 2000, and 2020, respectively, the watershed's mean annual soil loss increases by 15.5, 35.9, and 38.3 t/ha/y. Approximately 36 cm of the watershed's economically productive topsoil was lost throughout the study's twenty-nine-year period (1991–2020). According to the degree of erosion, 16 % of the watershed was deemed seriously damaged, while 70 % was deemed slightly degraded. Additionally, it is estimated for the year 2020 that 74,147.25 t/y of sediment (8.52 % of the total annual soil loss of 870,763.12 t) reach the Boyo watershed outlet. SW4 and SW5 were the two sub-watersheds with the highest erosion rates, requiring immediate conservation intervention to restore the ecology of the Boyo watershed.

Effect of the Material of Oil Pipelines with 90° Elbows on the Degree of Erosion Using Computational Fluid Dynamics

Effect of the Material of Oil Pipelines with 90° Elbows on the Degree of Erosion Using Computational Fluid Dynamics

Ecological response to global changes in Lake Genco, a remote alpine lake on the Southeast Tibetan Plateau, over the past two centuries

The ways in which natural ecosystems respond to global change have become an urgent concern to society. Lakes play a pivotal role in ecosystem changes because of their central position within watersheds and their involvement in various endogenous and cross-system ecological and biogeochemical processes, leaving natural archives accumulated in sediments over time. However, how lake ecosystems have responded to atmospheric changes during the past few centuries is still not fully understood. To analyse the process in more detail, we conducted a case study at Lake Genco, a remote alpine on the southeastern Qinghai-Tibetan Plateau (QTP) and recovered a 170-year history of lake's ecosystem from a 210Pb-dated sediment core. The air temperature increased between 1900 and 1950 CE and 1980 and 2020 CE. Geochemical and physical proxies (magnetic susceptibility, Sr/Ba, K/Al, Na/Al, Ti, Pb, P flux, TN and δ15Norg) indicated greater degrees of weathering and erosion, and higher nutrient loadings as terrestrial systems responded to atmospheric changes after 1900 CE. Higher primary aquatic productivity, richer biodiversity and weaker structural stability were found in Lake Genco between 1852 and 2017 CE, although the ecological response was quiet in terms of the compositional change in the diatom community, which was generally dominated by small planktonic Cyclotella ocellata. During warmer periods, diatom PC1 changed directionally due to the overall increase in the abundance of tychoplanktonic Fragilaria construens and periphytic Achnanthes minutissima and the decreasing abundance (∼10%) of C. ocellata. This study provides empirical evidence that ecological changes in remote lakes rely on interactions between the atmosphere and the landscape and helps us to understand the complexity of the various impacts of global climate change. More local and regional studies are needed to generalise the mechanism of biological responses to atmospheric changes in remote lakes, especially in the QTP.

Downslope variability in deep-water slope channel fill facies and stacking patterns

Lithologic variations in deep-water slope channel systems provide critical insight into sedimentary processes on deep-water slopes, and are a key control on natural resource distribution and connectivity in subsurface reservoirs associated with ancient deep-water systems. While many studies have described these variations at outcrop-scale along depositional strike (across-channel), few have focused on documenting along-depositional-dip changes due to: (1) the dearth of along-slope perspectives afforded by outcrops; or (2) limited resolution and coverage of subsurface data sets. In this study, slope channel elements (≤30 m thick; ≤400 m wide) and composite channelform bodies composed of ≥2 stacked channel elements (channel complexes and channel systems; >30 m thick; >400 m wide) were characterized along a 50-km-long depositional-dip-oriented outcrop belt of the Campanian-Maastrichtian Tres Pasos Formation (Chile) to constrain longitudinal changes in channel fill character and stacking patterns. Results show that channel elements become more sandstone-rich downdip. Outcrop observations are supported by channel element net-to-gross ratios (measures of sandstone proportion), which increase downdip. Sandstone-prone channel elements within channel complexes and channel systems are more prevalent downdip; however, variability in lateral and vertical offset between successive channel elements downdip results in a poor correlation between net-to-gross values and paleoslope position when composite channelform bodies are considered. These findings suggest that the along-slope distribution of coarse-grained sediment in channel systems is tied to the degree of coarse-grained sediment bypass and erosion that occurs along a slope. The results of this study provide a detailed perspective into downdip changes in slope channel fill and stacking patterns, and help clarify aspects of analogous subsurface reservoirs, including sandstone proportion trends for several scales of deep-water slope channel architecture.

Mechanism investigation on gear vibration-cavitation caused by tooth-pair lubricated contact

Elastohydrodynamic contact of gears under the influence of vibration induces cavitation and jet impact. To predict the evolution of cavitation and the degree of cavitation erosion in the gear contact region, the multi-phase flow cavitation model and gear dynamic model are coupled for simulating the cavitation effect in the gear lubrication region and the jet stresses at the tooth boundary under different load torques and rotational speeds. Moreover, the proposed model is confirmed to be valid through comparing to experimental results. The cavitation and jet impact intensity increase and mainly distribute at the outlet of tooth contact under high speed. Load torque mainly affects the cavitation oscillation, but there exists an expectation value that makes both the amplitude and intensity of the cavitation fluctuation and erosion low.

Probability of Erosion Utilizing Google Earth Engine and the RUSLE Method in the Tuntang Watershed

The Tuntang Watershed is an important watershed in Central Java. Management of watersheds in the Tuntang stream is a priority for various parties to carry out. One of the things that threatens the sustainability of the Tuntang watershed is erosion. The erosion rate can lead to sediment accumulation and siltation in the Tuntang River reservoir, which can cause catastrophic flooding. Flood disaster mitigation caused by erosion needs to be done, one of which is by calculating the erosion rate per year that occurs in the Tuntang watershed. This study calcultated the predicted erosion rate (per year in the Tuntang watershed) using the Revised Universal Soil Loss Equation (RUSLE) method, processed using the Google Earth Engine (GEE). Google offers a cloud-storage technology called GEE. Programming in JavaScript is required to operate GEE. GEE is a petabyte-scale data-based tool that can be used to analyze and archive geospatial data that is open source. The computing environment is designed for the processing of geospatial data, including the depiction of spatial analysis of satellite imagery. Data for RUSLE is obtained from the database in GEE, and the results can be imaged on a map. According to the study’s findings, the degree of soil erosion throughout the Tuntang Watershed was essentially constant, with Moderate erosion predominating in the majority of locations. Senjoyo Sub Watershed, Rowopening Sub Watershed, and Tuntang Hilir Sub Watershed are the primary locations with severe erosion. Rowopening Sub Watershed is the region that is the worst.

Investigation on the effect of particle parameters on the erosion and erosion prediction model of the Pelton turbine

The Pelton turbine will play a massive role in China's water conservancy and power generation development process. In practical engineering applications, sediment will erode the components of the Pelton turbine when they come into contact, threatening the safe and stable operation of the unit. Therefore, based on the Eulerian–Lagrangian method, this study analyzes the effects of particle size, concentration, and position angle on the degree and distribution of erosion of each component without considering the cavitation effect of the flow. The results show that the larger the particle size, the more concentrated the distribution, and the more severe the abrasion caused on the spray needle and water bucket. However, the degree of nozzle erosion weakens, and the erosion area increases. It was also found that the higher the concentration, the more severe the abrasion caused to each component. When the jet completely hits the position on the bucket, due to the low impact speed, the impact angle remains almost unchanged, resulting in less erosion. Finally, the classic Finnie model was refined by adjusting the average erosion rate, particle size, concentration, and rotation angle. This modification yielded an enhanced model, mainly showcasing improved performance for moderate particle sizes.

Geological setting, lead-zinc mineralization characteristics and its potential prospects in the Na Bop - Pu Sap area, Cho Don, Northeastern Vietnam

The Lo Gam structural zone is recognized as a crucial area for the occurrence of lead-zinc deposits in Northeast Vietnam, encompassing the distinguished territories of Cho Dien and Cho Don. Specifically, within the Cho Don area, the Na Bop-Pu Sap area emerges as particularly noteworthy owing to the considerable scale and quality of its lead-zinc ore deposits. In order to comprehensively investigate the geological attributes and lead-zinc mineralization phenomena prevalent in Na Bop-Pu Sap, a suite of analytical techniques including petrographic analyses, mineralogical examinations, scanning electron microscopy (SEM), and ICP-MS were employed. Furthermore, stable isotope investigations and single mineral sphalerite analyses were conducted to assess the origin of metal constituents and the physicochemical conditions conducive to ore genesis. The Na Bop-Pu Sap area is under the influence of the NW-SE fault system, with the ore structure predominantly manifesting as bands and veins aligned parallel to the foliations of hosted rock. This configuration suggests a close association between the formation of lead-zinc ore and the foliation processes occurring within the shear zones. The assemblage of ore minerals within the region primarily comprises galena, sphalerite, pyrite, pyrrhotite, and arsenopyrite. Integration of S and Pb isotopic analyses alongside single mineral sphalerite assessments reveals that the ore-forming solutions emanate from both magmatic activity and sedimentary sources, with lead-zinc ore deposition occurring at temperatures ranging from low to medium. Projections suggest that the Na Bop-Pu Sap mining area may exhibit relative degrees of erosion extending to depths of approximately 600 meters below the existing terrain surface. This comprehensive examination of the ore characteristics in the Na Bop-Pu Sap mine area yields invaluable insights, thereby advancing our understanding of the potential for deep-seated lead-zinc mineral resources within the Northeastern Vietnam.

Study on surface erosion threshold and erosion mass of bentonite applied in nuclear waste repository based on fractal structure characteristics

Bentonite exhibits good self-sealing performance and low permeability after hydration, and therefore is selected as a buffer material for high-level radioactive waste repositories, isolating the canisters containing nuclear waste from the external environment. The bentonite cushion directly contacts the surrounding rock and generates gels at the contact interface with fracture water. Surface erosion occurs once the shear stress exerted by the flowing water exceeds the erosion threshold of the bentonite gel, resulting in gel particle detachment from the soil–water interface and transport through fissure. The mass loss of the buffer by erosion will weaken its functionality as designed and directly endanger the long-term safety of the repository. The erosion behavior of bentonite is related to the structure of the gel formed by bentonite hydration. In this paper, the X-ray small-angle scattering experiments were used to prove that the gel structure has fractal characteristics and to obtain the mass fractal dimension. Based on the fractal structure of the bentonite gel, the erosion threshold that determines whether erosion will occur was quantified as a function of the solid volume fraction of the gel by taking the inter-particle attractive bond as the primary source of resistance. Furtherly, the cumulative erosion mass model that evaluates the extent of erosion was constructed to reveal the relationship between the cumulative erosion mass and cumulative water flow after the erosion has achieved stability. The proposed relations are verified by the experimental results from published literature and are of great significance for judging whether erosion will occur and evaluating the degree of erosion.

Vulnerability of Thermal Energy Storage Lining Material to Erosion Induced by Particulate Flow in Concentrated Solar Power Tower Systems.

Researchers from all around the world have been paying close attention to particle-based power tower technologies. On the King Saud University campus in the Kingdom of Saudi Arabia, the first integrated gas turbine-solar particle heating hybrid system has been realized. In this study, two different types of experiments were carried out to examine how susceptible prospective liner materials for thermal energy storage tanks were to erosion. An accelerated direct-impact test with high particulate temperature was the first experiment. A low-velocity mass-flow test was the second experiment, and it closely mimicked the flow circumstances in a real thermal energy storage tank. The tests were conducted on bare insulating fire bricks (IFBs) and IFBs coated with Tuffcrete 47, Matrigun 25 ACX, and Tuffcrete 60 M. The latter three lining materials were high-temperature-resilient materials made by Allied Mineral Products Inc. (AMP) (Columbus, OH, USA). The results showed that although IFBs coated with AMP materials worked well in this test, the accelerated direct-impact test significantly reduced the bulk of the bare IFB. As a result, lining substances must be added to the surface of IFBs to increase their strength and protection because they cannot be used in situations where particles directly impact their surface. On the other hand, the findings of the 60 h cold-particle mass-flow test revealed that the IFBs were not significantly eroded. Additionally, it was discovered that the degree of erosion on the samples of bare IFB was unaffected by the height of the particle bed.

Photogrammetric Investigation of Storm-Induced Erosion Process on Sandy Beach Profile in Medium-Scale Flume

In this study, laboratory experiments were conducted to investigate the influence of changes in storm wave height and water level on beach response in a medium-scale wave flume. A schematic storm was simulated (rising, apex, and waning phases). A non-intrusive photogrammetric method was used to collect high-resolution and synchronous data regarding the free surface water elevation and bed level, from which shoreline location, sandbar position, cross-shore sediment transport rates, and nonlinear wave parameters were derived. The cross-shore sediment transport was in agreement with previous laboratory measurements, including the monotonous exchange from foreshore erosion to shoaling zone accretion in most stages of the storm simulation. The surf zone was the main region supplying sediment for beach morphology modification and sandbar generation. The degree of storm erosion was not completely determined by the largest wave height and water level or the cumulative wave power of the apex phase. The largest gradients of the wave parameter sequence change occurred in the rising phase, and this was the main factor generating efficient beachface erosion. It induced an increase in sandbar size, accompanied by the cross-shore motion of maximum velocity amplitude, more violent disturbances of wave nonlinearity, and increased surf zone erosion, with these factors increasing beach instability and leading to more severe storm erosion. The large wave height and water level resulted in shoreline retreat, with a more significant swash zone erosion under a higher runup. The offshore sediment transport turned toward the onshore direction as the original large sandbar deteriorated under the decreasing wave parameter sequence in the waning phase.

Identification and simulation the response of storm-induced coastal erosion in the China Yellow sea

Storm events have a significant impact on coastal topography, which can subsequently lead to coastal erosion and ecological deterioration. Traditional field measurements are affected by environmental factors and consume substantial resources, making it difficult to conduct large-scale terrain, hydrodynamic and other monitoring tasks. Significant challenges still remain to identify the response of coastal processes to storm events due to the lack of field measured data. In this study, the response of coastal morphodynamical variations to extreme storm events was simulated by the coupled XBeach and FVCOM models and the storm-induced coastal evolution was evaluated in the China Yellow Sea. The costal morphodynamical variations under different wind conditions were also quantified. The results reveal that erosion dominated the supratidal zone while accretion mainly occurred in the subtidal zone. Comparing the coastal morphology before and after the storm, we found the alongshore currents were the primary factors influencing sediment transport. The degree of coastal erosion and accretion shift was positively correlated with the wind speed and direction. The present nested model may serve as a valuable tool for predicting future coastal erosion and accretion, contributing to more scientifically informed coastal management decisions. The study also provides a scientific basis for understanding the response mechanism of coastal morphodynamical process to extreme storm events and coastline evolution under global change.

The combined effects of tide and storm waves on beach profile evolution

Meso- to macro-tidal beaches are extensively distributed around the world. Water level determines the location where wave action can reach. Tide induced water level changes are the main component of total water level during typhoon landfall, which determines the extent and degree of beach erosion. Considering the tidal level wave height variation process in physical model experiments is crucial for the evaluation of beach erosion. This study presents the results of a new set of beach profile evolution process which considers the combined effects of tide and storm waves. Compared with the mean tidal level situation, tide induced water level variations significantly changes the erosion pattern of profile. The maximum erosion magnitude decreases by about 60% and the horizontal range increases by about 25%.

Hilly, Semi-Mountainous and Mountainous Areas Harbor Landraces Diversity: The Case of Messinia (Peloponnese-Greece)

Landraces are identified for their genetic diversity and heritage value. Geographically isolated areas are gradually recognized for their agricultural diversity and importance in conservation. One of the consequences of agricultural intensification is an increase in crop uniformity and hence a reduction in the landraces’ genetic resources. Messinia, located in Southwest Peloponnese, Greece, is characterized by a diverse terrain and smallholdings. The geomorphological character of the area and farmers’ selections have led to new landraces (local varieties) with unique traits and specific adaptations. A total of 110 villages/settlements were visited between 2013–2016, aiming to explore the existing wealth of landraces and the degree of genetic erosion. The genetic material collected and the testimonies extracted from local communities were compared to data from past expeditions, gene banks, and portal databases. Of the 427 collected samples, the majority belonged to annual vegetable or pulse species, indicating the genetic diversity of the groups, which was likely related to their culinary value. Perennial crops are priced both as commercial and staple crops, with olive trees dominating the agricultural landscape. Genetic erosion and production decline were noticed for cereals. It is concluded that socio-cultural and agricultural trends have a strong influence on the survival of landraces. Without exhausting the agricultural wealth of the region, the present study suggests that Messinia is an agrobiodiversity hotspot that includes neglected crops.

Investigation on sediment erosion in bucket region of Pelton turbine considering cavitation

In the context of constructing high-head hydro-power stations, the Pelton turbine assumes a critical role as the primary energy converter. This study employs the Eulerian–Lagrangian method to simulate the multi-phase flow occurring within the Pelton turbine bucket. Furthermore, it introduces a novel aspect by investigating and comparing the effects of cavitation on erosion within the bucket region under varying conditions of sediment-water, involving different particle sizes and concentrations. The research findings unveiled several key insights. Primarily, cavitation predominantly influences the flow characteristics of particles at the air–liquid interface, while particles with larger sizes tend to concentrate in the center of the jet. Consequently, cavitation's impact on erosion is more pronounced in the case of smaller-sized particles. Moreover, the study revealed that cavitation can either exacerbate erosion under high particle concentration conditions or mitigate it when particle concentration is low. Furthermore, the investigation highlighted variations in the degree of erosion and the affected area of the bucket based on different position angles. Particularly, at a position angle of 65°, the presence of water vapor induced by cavitation alters particle trajectories, thereby modifying the overall erosion pattern of the bucket. These findings collectively contribute to a deeper understanding of the complex interplay between cavitation and erosion within the Pelton turbine bucket.

EFFECTIVENESS OF BIOLOGICAL PRODUCTS AND ORGANIC FERTILIZERS FOR COTTON ON IRRIGATED ERODED TYPICAL SIROZEMS

The article presents the influence of organomineral and biological preparations on the growth and development of cotton seedlings in conditions of irrigated typical sierozem. Also, dependingon the degree of soil erosion, the growth rate of cotton varies. According to the data obtained, higher rates were observed in the option with the use of biological product Rizokom-1 and in the collected soil compared to other options.

Numerical assessment of erosion wear in Pelton turbine injectors

The Pelton turbine is the main type of turbine used to develop hydropower resources in high-head sections and is more sensitive to sediment erosion. To analyse the causes of asymmetric erosion distribution on the injector surface, a solid-liquid-gas three-phase numerical study of Pelton turbine injectors is carried out. The results indicate that as the sediment diameter increases, the differences in particle discharge distribution among the jets of each branch also increase, and the asymmetric erosion distribution on the injector surface becomes stronger. The particle trajectory is influenced by the vortex structure, and fine particles mainly cause banded erosion, while coarse particles cause sheet erosion. At constant inflow conditions, the particle residence time is related to erosion morphology, and the particle velocity and the number of impacts affect the erosion rate on the injector surface. It is recommended to avoid long-term operation of the turbine under conditions of excessively small or large sediment diameters and to pay attention to the sediment erosion degree of the middle branch needle and the end branch nozzle of the water supply mechanism. The research findings of this paper can provide references for further optimization of the design, operation, and maintenance of the Pelton turbine.