Erosion Degradation Research Articles

Erosion degradation analysis of rice husk ash-rubber-fiber concrete under hygrothermal environment

To study the resistance of rice husk ash-rubber-fiber reinforced concrete (RRFC) to dry–wet cycle/chloride erosion under a hygrothermal environment, the optimal combination was selected by an orthogonal test. The peak strain, residual strain, and fatigue damage strength of the optimal group of RRFC samples under cyclic loading and unloading after dry–wet cycle/chloride erosion under different environments and temperatures were compared and analyzed. After that, microscopic analysis and anti-erosion mechanism analysis were carried out. The results show that the axial peak and residual strain of RRFC specimens increase continuously during the repeated loading–unloading process, and the increase of axial peak and residual strain in the first five cycles is the most obvious. Among them, RRFC has the most significant increase in axial peak strain after 14 dry–wet cycles, which is 11.73%. The rice husk ash reacted with Ca(OH)2 in the specimen to precipitate C—S—H gel, which improved the specimen’s corrosion resistance and fatigue resistance. The rubber in the specimen has high elasticity, which reduces the fatigue damage of the specimen during cyclic loading and unloading, thus showing higher fatigue failure strength.

Cavitation erosion of the AA7050 aluminum alloy in 3.5 wt% NaCl solution—Part 1: mitigating effect by corrosion

The corrosion in 3.5 wt% NaCl solution caused a mitigated weight loss of the aluminum alloy 7050 (AA7050) under cavitation erosion condition. The mechanism was observed using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electro back-scattered diffraction (EBSD), and potentiodynamic polarization. Both in deionized water and in 3.5 wt% NaCl solution, the cavitation erosion degradation of the AA7050 was mainly attributed to fatigue fracture like peeling off of surface layer materials. The corrosion significantly mitigated the weight loss of AA7050 under cavitation erosion condition because the loose surface oxide film (generated by corrosion) dissipated the cavitation impact energy and therefore alleviated the stress concentration on the alloy surface.

Reliability-based leading edge erosion maintenance strategy selection framework

Leading edge erosion has become one of the most prevailing failure modes of wind turbines. Its effects can evolve from an aerodynamic modification of the properties of the blade to a potential structural failure of the leading edge. The first produces a reduction of energy production and the second can produce a catastrophic failure of the blade. Considering the uncertainties and constraints involved in the design of optimal operation and maintenance (O&M) strategies for offshore assets and the influence of site-specific parameters on the dynamics of this particular failure mode, the task becomes complex. In this study, a framework to evaluate the influence of different maintenance strategies considering uncertainties in weather, material behaviour and repair success is presented. Monte Carlo Simulation (MCS) is used alongside a computational framework for Leading Edge Erosion (LEE) degradation to evaluate the lifetime cost distribution and probability of failure of the chosen maintenance strategies. The use of the framework is demonstrated in a case study considering a 5-MW offshore wind turbine located in the north of Germany. The influence of the modification of the maintenance interval or time between repairs and the comparison with maintenance activities executed only during months with milder weather is analysed in terms of cost and reliability. A Pareto front plot considering the probability of failure and the median of the cost is used to jointly compare strategies considering both aspects to provide a tool for risk-informed maintenance selection. Finally, the potential benefits of condition-based maintenance and autonomous decision-making systems are discussed. The case of study shows the benefits of repairs during summer months and the importance of the relation risk/O&M cost for different maintenance strategies.

Impacts of long-term organic manure inputs on cultivated soils with various degradation degrees

With an increasing concern of soil health and sustainable development, organic manure application has been readdressed in recent years. In Northeast China, the agricultural industry is highly developed and organic manure resources are abundant, but soil degradation is serious due to extensive expansion of cultivation. Currently, limited information is available on how soils with various degradation degrees respond to long-term manure fertilization. Given that, a comparative study was conducted based on soil functional assessment of croplands with over 35 years of manure fertilization (maize straw compost, SA; cattle manure, CA) and various degradation degrees (none, light, moderate, and heavy). Soils in these croplands were loess-derived Mollisols and concentrated on a gentle to flat slope. Except for the difference in manure fertilization (SA and CA), similar field managements were adopted for these croplands during the past 35 years. Results showed that the impacts of erosion degradation and manure fertilization on soil physical structure lasted across the whole profile (0 ∼ 120 cm), while their impacts on soil nutrient properties were concentrated in shallow layers (<50 cm). Meanwhile, erosion degradation dominated 17.9% of the variance of soil physical structure, and soil profile depth contributed to 15.9% of soil nutrient variation. According to field validation regarding soil erosion modulus and crop yield, principal component analysis (PCA) with a nonlinear scoring method showed a good performance on the integrated soil functional index (ISI) assessment in this study area. The ISI of these croplands was found to be minimally characterized by BD, SOC, TN, AK, sand content, and CEC (R2 >0.64, p < 0.001). In addition, manure fertilization could significantly improve the ISI and maize yield for degraded soils, but had a slight impact on these two indicators for non-degraded soils. In terms of contribution to ISI improvement, SA (1.79% ∼ 283.73%) generally outperformed CA (4.53% ∼ 212.83%), while the latter was more effective in altering soil structure in deep layers (>70 cm). Generally, the ISI and maize yield were more susceptible to erosion degradation than manure fertilization. The obtained results provide useful information for a better cropland management in Northeast China.

Study on soil hydraulic properties of slope farmlands with different degrees of erosion degradation in a typical black soil region.

In order to explore the impact of soil erosion degradation on soil hydraulic properties of slope farmland in a typical black soil region, typical black soils with three degrees of erosion degradation (light, moderate and heavy) were selected as the research objects. The saturated hydraulic conductivity, water holding capacity and water supply capacity of the soils were analyzed, as well as their correlations with soil physicochemical properties. The results showed that the saturated hydraulic conductivity of black soils in slope farmlands decreased with erosion degradation degree, which was higher in 0-10 cm soil layer than in 10-20 cm soil layer. The water holding capacity and water supplying capacity of typical black soils also decreased with the increase of erosion degradation degree, and both of them were stronger in the upper soil than in the lower soil. With the aggravation of erosion degradation of black soils, soil organic matter content decreased while soil bulk density increased, leading to the decline of soil hydraulic conductivity. The increase of soil bulk density and the decrease of contents of organic matter and >0.25 mm water stable aggregates were the main factors leading to the decrease of soil water holding capacity. These findings provide scientific basis and basic data for rational utilization of soil water, improvement of land productivity and prevention of soil erosion.

Biodegradable implants based on photo-cross-linked aliphatic polycarbonates for long-acting contraception

In this study, a new class of biodegradable contraceptive implants was prepared via the UV irradiation molding method, among which, progestin levonorgestrel (LNG) was used as a model drug. Photo-cross-linked aliphatic polycarbonates (APCs), namely, poly (trimethylene carbonate-co-2,2′-dimethyltrimethylene carbonate) [P(TMC-co-DTC)] elastomers, were used as the drug delivery matrix. The results obtained from the degradation experiments carried out in Sprague-Dawley (SD) rats showed that the cross-linked elastomer had the degradation characteristics of the surface erosion degradation mechanism, with no generation of acid degradation products, and excellent form-stability, which met the performance requirements of the matrix for a long-acting sustained-release delivery system. The in vitro cytotoxicity tests and histological and immunohistochemical evaluations showed good biocompatibility and biosafety of the elastomer matrix material and contraceptive implants. Subsequently, the implant formulations were screened by in vitro release experiments, and their release kinetics were explored. Finally, in the evaluation study of the in vivo anti-fertility effect, the implants exhibited excellent dimensional stability and were degraded by a surface erosion mechanism. LNG achieved a stable and sustained release in female SD rats, maintaining a long-acting contraceptive duration of up to 4 months. The contraceptive implants obtained in this study could be used to address the limitations of currently available formulations, which required secondary surgical removal and a single means of regulating drug release kinetics. Therefore, these implants could provide a new option for birth control needs and may be of significance in reducing the incidence of induced abortion and protecting female fertility.

Effect of large sized reed fillers on properties and degradability of PBAT composites

AbstractIn this paper, large‐size reeds were introduced into PBAT to prepare high‐performance biodegradable composites by high‐speed blending without compatibilizer. Subsequently, the effects of large‐size reeds on the composite properties and biodegradation behavior were further investigated. The length of the reed in composites reaches to ~1.88 mm. It was found that all composites showed larger modulus and flexural strength than PBAT, and a significant increase in heat deflection temperature. By mixing 60% reed and PBAT, the bending strength, bending modulus, and heat deflection temperature reached 23.9 ± 0.4 MPa, 1237 ± 143 MPa, and 71.8°C, respectively. Biodegradation tests showed that the primary bond‐breaking site of PBAT was the C=O group. Compared with pure PBAT, the composites exhibited more significant mass loss, decreased thermal stability, increased melting point, and decreased crystallinity during degradation. A surface erosion degradation model for the composites was proposed. The research provides a scientific basis for applying high‐performance biodegradable composites to biodegradable blister and injection molded products.

Relationship between mechanical load and surface erosion degradation of a shape memory elastomer poly(glycerol-dodecanoate) for soft tissue implant.

Poly(glycerol-dodecanoate) (PGD) has aroused increasing attention in biomedical engineering for its degradability, shape memory and rubber-like mechanical properties, giving it potential to fabricate intelligent implants for soft tissues. Adjustable degradation is important for biodegradable implants and is affected by various factors. The mechanical load has been shown to play an important role in regulating polymer degradation in vivo. An in-depth investigation of PGD degradation under mechanical load is essential for adjusting its degradation behavior after implantation, further guiding to regulate degradation behavior of soft tissue implants made by PGD. In vitro degradation of PGD under different compressive and tensile load has proceeded in this study and describes the relationships by empirical equations. Based on the equations, a continuum damage model is designed to simulate surface erosion degradation of PGD under stress through finite element analysis, which provides a protocol for PGD implants with different geometric structures at varied mechanical conditions and provides solutions for predicting in vivo degradation processes, stress distribution during degradation and optimization of the loaded drug release.

A wind turbine blade leading edge rain erosion computational framework

Blades are one of the most important components, in terms of capital and operational costs, of wind turbines. The experienced acquired by the industry in the latest decades has shown that leading edge erosion is a problem of concern that impacts the reliability of the blade and the power production of the turbine, among others. This study provides a framework to estimate leading edge erosion evolution and energy production degradation throughout time to apply in operation and maintenance decision making. It is based on the generation of synthetic wind and rain data based on observations from the site and ERA5 reanalysis data, whirling arm test data of erosion protection coatings, along with aerodynamic polar curves for clean and eroded airfoils of the blade. Rain erosion is calculated based on impingement, and assumed to be linearly accumulated using the Palmgren–Miner rule. Synthetic wind and rain time series are used to evaluate 25-year erosion degradation and energy production scenarios. A case study using the 5MW NREL’s wind turbine located in the North Sea has been analysed with the proposed framework showing maximum annual energy production losses in the range of 1.6–1.75% and first erosion failure between years 2 and 6.

Геоинформационный анализ рельефа Кумо-Манычской впадины

The territory of the Kumo-Manych depression is located in the fault zone of the tectonic plate and is a characteristic floodplain structure with a large number of swamps, lakes and channels. This territory is characterized by a high anthropogenic load associated with the intensive use of land for agricultural production and, as a consequence, with the manifestations of degradation processes. The relevance of the analysis of the relief of the territory is due to the influence of geomorphological characteristics on the magnitude and dynamics of erosion degradation of land. The methodological basis of the research is the catchment approach, which provides the structuring of landscape structures. The research methodology is based on the use of geoinformation systems for the development of analytical maps based on digital terrain models and geostatistical analysis of the spatial distribution of its structure. The results of the research are presented by analytical maps that allow us to determine the characteristics of the terrain of the terrain with their proximity to a certain location. These results make it possible to assess the erosion hazard of such sites and to develop measures in advance to prevent their degradation. Thus, geoinformation analysis of the relief of the Kumo-Manych depression allowed us to establish that about 47 % of the area of the research site is located in the height range from 20 to 80 m. The steepness of the slopes is insignificant, 52.7 % of the territory has a steepness of less than 1°. Another 38.2 % of the slopes have a steepness of less than 2°. Uncultivated slopes with a steepness of more than 8° occupy less than 1 % of the landfill area.

Bulk Erosion Degradation Mechanism for Poly(1,8-octanediol-co-citrate) Elastomer: An In Vivo and In Vitro Investigation.

As a biodegradable elastomer, poly(1,8-octanediol-co-citrate) (POC) has been widely applied in tissue engineering and implantable electronics. However, the unclear degradation mechanism has posed a great challenge for the better application and development of POC. To reveal the degradation mechanism, here, we present a systematic investigation into in vivo and in vitro degradation behaviors of POC. Initially, critical factors, including chemical structures, hydrophilic and water-absorbency characteristics, and degradation reaction of POC, are investigated. Then, various degradation-induced changes during in vitro degradation of POC-x (POC with different cross-linking densities) are monitored and discussed. The results show that (1) cross-linking densities exponentially drop with degradation time; (2) mass loss and PBS-absorption ratio grow nonlinearly; (3) the morphology on the cross-section changes from flat to rough at a microscopic level; (4) the cubic samples keep swelling until they collapse into fragments from a macro view; and (5) the mechanical properties experience a sharp drop at the beginning of degradation. Finally, the in vivo degradation behaviors of POC-x are investigated, and the results are similar to those in vitro. The comprehensive assessment suggests that the in vitro and in vivo degradation of POC occurs primarily through bulk erosion. Inflammation responses triggered by the degradation of POC-x are comparable to poly(lactic acid), or even less obvious. In addition, the mechanical evaluation of POC in the simulated application environment is first proposed and conducted in this work for a more appropriate application. The degradation mechanism of POC revealed will greatly promote the further development and application of POC-based materials in the biomedical field.

Ecological Security and Ecosystem Quality: A Case Study of Xia-Zhang-Quan Metropolitan Area in China

Ecological security patterns are an effective tool by which to balance economic development with ecological protection. This study used the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model in conjunction with circuit theory to evaluate ecosystem quality from four dimensions: background conditions, topography, landscape structure, and ecological resistance. Our objective was to identify ecological “pinch points” in order to create an ecological security pattern that would be sustainable under a range of land use functions. We selected as the research target the Xia-Zhang-Quan metropolitan area in China due to the extensive soil erosion and general degradation of ecosystems caused by its rapid socio-economic development. Our analysis identified 17 ecological source sites covering 11,512 km2, which accounts for 45.36% of the total area. The inter-source corridor includes 31 key corridors and 10 potential corridors covering 3305 km. The average ecosystem quality of this area was estimated at 0.65 at an optimal granularity of 400 m. The distribution of resistance values in the study area was relatively concentrated with the land divided into an ecological buffer zone (34.6%), an environmentally sensitive zone (10.9%), and a blocking zone (9.2%). Our analysis also revealed various corridors based on the regional and functional characteristics of ecological elements and improvement strategies at the pinch points to help restore the function of ecological sources. Protection of these corridors will help to maintain regional ecological security patterns and optimize the structure of ecological spaces with the aim of achieving sustainable development.

Synecology diagnostics methodology transformations of the structural and functional organization forest ecosystems

The main directions of development of biotic diagnostics of disruption of forest ecosystems with modern methodical approaches to assessing their condition according to selection criteria are considered. The issue of indicating the state of the forest ecosystem by the structural parameters of biocomponents occupies an important position among a number of ecological and biological studies. It was established according to an analytical review of the literature. To solve the existing methodological problems of biodiagnosis of anthropogenic transformation of forest ecosystems, it is necessary to evaluate the current state, the mechanisms of their change, which are caused by environmental threats, according to various criteria, and bioindication should be carried out according to ecosystem indicators. Informative diagnostic signs of recreational disturbance of forests of various categories of functional purpose in the initial stages changes are biomorphological, ecomorphic, systematic structures of the grass layer, ecological strategies and ecological valences of species, diversity indices. From the III stage of digression, the tree stand (sanitary, vital structures, taxation indicators) and the soil surface (distribution by status categories) reveal the indicator signs. Violation of recreational and health forests and park plantations in city conditions is manifested by an increase in the contribution of evrybiont species according to edaphic factors, therophytes and species with a primary and secondary strategy, which have the R-sign, a higher index of adventitization of flora (over 20%). To diagnose the consequences of water erosion of soil in mountain systems (Carpathians, Crimea), it is advisable to use the characteristics of different layers of the tree stand and grass layer at all stages of soil erosion digression. Representatives of Poaceae, Caryophyllaceae, Asteraceae with dominance of cryptophytes and therophytes, species with CSR- and R-type strategies are representative. Indicative signs are the ratio of rhizome species to species without formations, as well as species with a creeping aerial shoot to a rosetteless type of shoot. On the gradient of increasing water-erosive transformation of the ecosystem, diagnostic indicators of the structure of ecomorphs are the edaphic factor of humidity and salt regime of the soil, but only by the change in the share of the herbaceous fractions of stenobiont and evrybiont species. Diagnostic signs of moderate and intensive soil erosion degradation are changes in the values ​​of diversity and dominance indices.

Науково-методичні засади дистанційного агроекологічного моніторингу та прогнозування

Goal. To improve the system of remote agroecological monitoring and forecasting of the impact of climate warming on grain yields. Methods. NOAA STAR NESDIS (National Environmental Satellite Data Information Services) satellite data were used to determine the climatic parameters of the earth’s surface. The impact of warming on vegetation was determined by the NDVI satellite indicator from the website STAR NESDIS NOAA — Satellite Applications and Research of NOAA’s National Environmental Satellite Data Information Services — Center for the Use of Satellite Research and Information of the US National Oceanic and Atmospheric Administration. Erosion degradation of agricultural landscapes was performed using an unmanned aerial vehicle of flying wing type. The Pentax W60 camera was used as a sensor, with the following camera settings: 1/2.3” CCD matrix, shutter when shooting 1/51/320. ISO 501600 in Digital SR mode (5 MP), in serial mode. Surveying routes were constructed in the form of a spiral to avoid distortion of orthophotos in the analysis. The analysis was performed using the following software: AgisoftPhotoscan, ErdasImage. Results. Information is given on the implementation of the new research program of the National Academy of Agrarian Sciences “Satellite agroecological monitoring, agro-resource management and forecasting the impact of climate change on the productivity of agro-ecosystems (“Agrocosmos”) based on the report of Academician NAAS O.I. Furdychko for 2021. It is shown that the use of remote sensing/GIS technologies is an effective tool for operational monitoring of agricultural landscapes, moisture supply, drought, erosion degradation, and forecasting the impact of global warming on grain yields. The efficiency of using satellite indicators in forecasting grain productivity was established. Conclusions. According to published sources and experimental data, remote sensing methods in the agroecological monitoring system are an effective tool for obtaining up-to-date information on the state of agricultural resources, moisture supply, manifestations of desertification, soil erosion, and forecasting. According to satellite data, it is possible to perform an index analysis of crop productivity and make an early forecast of their yields. The expediency of using unmanned aerial vehicles (UMAV) in determining the erosion degradation of soils was proved. An appropriate method of using UMAV was proposed, which has been tested on the territory of the Bohodukhiv administrative district of the Kharkiv region.

Restoring geomorphic integrity in urban streams via mechanistically-based storm water management: minimizing excess sediment transport capacity

Stream channel erosion, enlargement, and habitat degradation are ubiquitous in urban watersheds with conventional stormwater management that increase channel-eroding flows relative to undeveloped watersheds. Hydrologic-based restoration aims to discharge a more natural flow regime via stormwater management interventions. Whether such interventions facilitate geomorphic recovery depends, in part, on the degree to which they restrict discharges that would otherwise contribute to channel erosion. Erosion potential (E), the ratio of post-developed to predeveloped sediment transport capacity, provides a simplified, mechanistic framework to quantify the relative influence of stormwater interventions on the geomorphic effectiveness of the flow regime. This paper compiles ca. five years of data following stormwater-based interventions in three distinct settings in the United States and Australia to demonstrate how the E framework can elucidate the role of hydrologic restoration interventions in facilitating trajectories of geomorphic recovery (or lack thereof). In a previously developed watershed with unstable streams, substantial reductions in E in one stream coincided with a trajectory of geomorphic recovery, whereas the control stream without E-reducing interventions exhibited continued instability. Furthermore, a stream downstream of a greenfield development that optimized their stormwater control measures to match the sediment transport capacity of the predeveloped regime (E = 1) was able to maintain a recovery trajectory in a legacy-impacted setting that is otherwise highly susceptible to hydromodification. Streambed material size, channel evolution stage, and the hydrogeomorphic setting also likely affect the level of E reduction necessary to promote geomorphic recovery, with coarser-grained and over-widened streams potentially needing less reduction than finer-grained and more entrenched channels. Although available space and funding will limit the ability to fully reduce E in previously developed watersheds, these case studies underscore the value of using stormwater control measures to maximize reductions in E if geomorphic stability is a goal of stormwater interventions.

WATER SOIL EROSION IN RIGHT-BANK UKRAINIAN FOREST-STEPPE ZONE

Problem Statement and Purpose. A water soil erosion is one of the most important ecological problems of the world because in the result of it the soil cover completely destroys and is not able to renew for a long time. In opinion of dr. Montgomery D., the loses of agricultural soils even limited the lifetime of ancient civilizations and the same problem closely touches today human being. Following to the information of scientists in 1970-s, about 430 million ha of lands were destroyed in different countries because of water soil erosion. Annual loses of product lands on our planet equal 5–7 million ha. In Ukraine at the end of first decade of 2000s following to National report (2010) the square of eroded agricultural lands equaled 15.954 million ha or 38.4 per cent of their common territory including 12.940 million ha of arable lands or 39.9 per cent. On average the soil loses about approximately 15 t/ha/year. Thereby the purpose of the study is a spatial distributed quantitative assessment of the intensity of erosion soil loses in the right-bank forest-steppe zone of Ukraine and definition of arable squares with different rates of erosion load considering present climate changes and land use peculiarities. Data &amp;Methods. For the estimation of average soil wash off three typical slope plots (К1-р, К2-р, К3-р) were used. The plots are situated within the territory of Educational and Scientific Stationary of the Odesa I. I. Mechnikov National University that is in Podilsk district of the north part of Odesa region. This territory is on south hills of Podolska upland in forest-steppe zone. The plots are the different parts of small valleys slopes which are annual plowed up and used for growing of the most profit-making crops – wheat, corn, barley and sunflower. No any scientifically based crop rotation uses there at least for the last twenty years. The spatial distributed physical and statistical model of soil wash off and accumulation was used as a working model for the estimation of average annual soil loses consideringthe peculiarities of land cultivation and anti-erosion crops properties. The model was developed in Department of Physical geography, Nature Management and Geoinformation Technology of Odesa I. I. Mechnikov National University and realized in GIS‑package PCRaster (Utrecht University, Netherlands). Results. The quantitative assessment of today erosion soil loses on typical plots considering land use demonstrates very high rate of soil erosion degradation which is obviously representative for the most territories of the right-bank forest-steppe zone of Ukraine. Areas of more than 20 t/ha/year wash off equal 23–27 per cent. Areas of less than 2 t/ha/year wash off where the intensity of soil erosion equals to soil restoration are about one third of all arable lands. The average values of wash off for plots К1-р, К2-р, К3-р are 14.2; 26.3 and 14.8 t/ha/year respectively. However, these values are not above the same ones obtained earlier, but even some less. This is due to the decreasing of soil erosion because of snow melting in the spring which is connected with global warming. But simultaneously the hydrometeorological conditions of rainstorm erosion have not change. And essential decreasing of wash off has not happened because the part of snow melting erosion is only 15–20 per cent in the right-bank forest-steppe zone of Ukraine. The huge values of average wash off and significant areas with high and very high wash off (about one third of arable lands) evidence about decreasing of economic and ecological worth of lands commonly. Applying of soil protection crops rotation well influence on soil decreasing the rate of erosion. The plowing of lands with great slopes (6–7° and more) and using them for row crops without rotation leads to catastrophic wash off and increasing of areas with high erosion danger. Such lands need to be exclude of plowing up.

A novel optimal data set approach for erosion‐impacted soil quality assessments—A case‐study of an agricultural catchment in the Chernozem region of Northeast China

AbstractBecause soil erosion is a primary cause of land degradation globally, it has received increasing attention in food production regions, such as the Chernozem region of Northeast China. This study assessed soil quality under soil erosion degradation using a novel optimal data set (ODS) approach and a comparative minimum data set (MDS) approach to derive soil quality indices (SQIs) within an agricultural watershed in Heilongjiang Province, China. The selection of SQIs was contingent on 15 physical, chemical, and microbial properties measured at 52 grids. Soil erosion rates were determined using the Cs‐137 technique. Results showed that SQIs derived from the ODS and MDS approaches were strongly correlated (r = 0.91, p &lt; 0.01). However, soil quality inferred by SQIs varied significantly between erosion and deposition sites, namely, increasing from upstream to midstream to downstream areas. Changes in SQIs and erosion rates exhibited spatially opposing trends, reflecting the impact of soil erosion on soil quality, which was also confirmed by comparing representative soil properties at erosion and deposition sites. The ODS approach using the optimal fingerprinting factor screening procedure of the composite fingerprinting approach is a cause‐related method that uses a relatively strict indicator selection procedure, which mainly includes sample groupings, Kruskal–Wallis H test, discriminant function analysis, and conservative behaviour tests of factors. Thus, it can theoretically obtain more reliable results compared to MDS. Further studies are nevertheless needed to assess the feasibility of this novel approach in other cases.

High-Temperature Solid Particle Erosion Behavior of Laser Powder Bed Fused Inconel 718

Abstract The failure of turbine blades due to solid particle erosion is a serious concern in aviation applications. This research investigates the solid particle erosion behavior of laser powder bed fused IN718 alloy for the effect of temperature (400 °C, 500 °C, and 600 °C) and impact angle (45 deg and 90 deg) in a gas-jet erosion setup. The erosion rate progressively increased with the test temperature and it is significantly higher in the 45 deg eroded samples. The eroded samples were characterized for residual stress distribution, surface topography, and surface roughness using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and 3D optical profilometer. Compressive residual stress is evident in all eroded samples, and higher residual stress is measured in the 90 deg eroded samples. Ploughing, crater lip formation, and cracking are the erosion features observed in the 45 deg eroded samples. In comparison, localized plastic deformation, platelet mechanisms, and cracked ridges are observed in the 90 deg eroded samples. Crack formation at 600 °C test condition is attributed to severe erosion degradation in both the impact conditions (45 deg and 90 deg). The as-printed and solution-double aged samples were thoroughly investigated for microstructure and microhardness distribution at the region parallel and perpendicular to the build direction.

The Degradation of Synthetic Polymeric Scaffolds With Strut-like Architecture Influences the Mechanics-dependent Repair Process of an Osteochondral Defect in Silico

Current clinical treatments of osteochondral defects in articulating joints are frequently not successful in restoring articular surfaces. Novel scaffold-based tissue engineering strategies may help to improve current treatment options and foster a true regeneration of articulating structures. A frequently desired property of scaffolds is their ability to degrade over time and allow a full restoration of tissue and function. However, it remains largely unknown how scaffold degradation influences the mechanical stability of the tissue in a defect region and, in turn, the regenerative process. Such differing goals–supporting regeneration by degrading its own structure–can hardly be analyzed for tissue engineered constructs in clinical trials and in vivo preclinical experiments. Using an in silico analysis, we investigated the degradation-induced modifications in material and architectural properties of a scaffold with strut-like architecture over the healing course and their influence on the mechanics-dependent tissue formation in osteochondral defects. The repair outcome greatly varied depending on the degradation modality, i.e. surface erosion or bulk degradation with and without autocatalysis, and of the degradation speed, i.e. faster, equal or slower than the expected repair time. Bulk degradation with autocatalysis, independently of degradation speed, caused the mechanical failure of the scaffold prior to osteochondral defect repair and was thereby deemed inappropriate for further application. On the other hand, scaffolds with strut-like architecture degrading by both surface erosion and bulk degradation with slow degradation speed resulted in comparably good repair outcomes, thereby indicating such degradation modalities as favorable for the application in osteochondral defects.

Modeling and Monitoring Erosion of the Leading Edge of Wind Turbine Blades

Leading edge surface erosion is an emerging issue in wind turbine blade reliability, causing a reduction in power performance, aerodynamic loads imbalance, increased noise emission, and, ultimately, additional maintenance costs, and, if left untreated, it leads to the compromise of the functionality of the blade. In this work, we first propose an empirical spatio-temporal stochastic model for simulating leading edge erosion, to be used in conjunction with aeroelastic simulations, and subsequently present a deep learning model to be trained on simulated data, which aims to monitor leading edge erosion by detecting and classifying the degradation severity. This could help wind farm operators to reduce maintenance costs by planning cleaning and repair activities more efficiently. The main ingredients of the model include a damage process that progresses at random times, across multiple discrete states characterized by a non-homogeneous compound Poisson process, which is used to describe the random and time-dependent degradation of the blade surface, thus implicitly affecting its aerodynamic properties. The model allows for one, or more, zones along the span of the blades to be independently affected by erosion. The proposed model accounts for uncertainties in the local airfoil aerodynamics via parameterization of the lift and drag coefficients’ curves. The proposed model was used to generate a stochastic ensemble of degrading airfoil aerodynamic polars, for use in forward aero-servo-elastic simulations, where we computed the effect of leading edge erosion degradation on the dynamic response of a wind turbine under varying turbulent input inflow conditions. The dynamic response was chosen as a defining output as this relates to the output variable that is most commonly monitored under a structural health monitoring (SHM) regime. In this context, we further proposed an approach for spatio-temporal dependent diagnostics of leading erosion, namely, a deep learning attention-based Transformer, which we modified for classification tasks on slow degradation processes with long sequence multivariate time-series as inputs. We performed multiple sets of numerical experiments, aiming to evaluate the Transformer for diagnostics and assess its limitations. The results revealed Transformers as a potent method for diagnosis of such degradation processes. The attention-based mechanism allows the network to focus on different features at different time intervals for better prediction accuracy, especially for long time-series sequences representing a slow degradation process.