Erosion Damage Research Articles

Pore fractal characteristics and ANN model of polyacrylonitrile fiber reinforced concrete under the synergistic effects of freeze-thaw and erosion

The degradation of the concrete pore structure is a major concern among scholars due to its negative impact on durability. This study conducted a salt freezing test on polyacrylonitrile fiber concrete (PANFRC) using a composite freeze-thaw medium consisting of Na2SO4, MgSO4, and NaCl (5 % + 5% + 3.5 %). The pore volume fractal dimension was determined by analyzing the T2 spectrum obtained through nuclear magnetic resonance technology. The study explored the influence of different types of pores on frost resistance and developed an artificial neural network-based machine learning model to predict macroscopic frost resistance using the pore volume fractal dimension. The experimental findings indicate that plain concrete exhibits a density loss of 4.67 % upon failure, whereas the density loss in PANFRC is reduced to less than 3 %. The frost resistance durability index is observed to improve as the fiber mass fraction increases within specific ranges. Notably, when the fiber content surpasses 1.2 kg/m³, the durability factor (DF) can be effectively doubled. Drawing from the concept of freeze-thaw cycles, a novel frost-thaw erosion damage model was developed, which incorporates the influence of fiber content under the combined action of freeze-thaw cycles and erosion. The analysis of pore dimensions reveals that the fractal characteristics become more pronounced with the increase in pore size, although this does not extend to the micro-pore range (i.e., those smaller than 0.1 μm). In comparison to other machine learning algorithms, the ANN demonstrates its superiority by establishing a meso-macro transfer prediction model with enhanced generalization capabilities.

Study on the influence of water supply and drainage pipeline damage on urban silt ground collapse

Underground drainage pipelines play crucial roles in urban construction and development. Over time, these pipelines may incur damage and leakage due to aging and changes in surrounding loads. Ruptures and leaks in pipelines can lead to water seepage through cracks, resulting in erosion of surrounding soil layers and the formation of underground cavities. The loss of support in the soil above these cavities can lead to structural instability and eventual ground collapse. Such collapses can disrupt urban transportation systems, leading to significant social and economic consequences. This study specifically investigates ground collapse phenomena resulting from damage to drainage pipelines in silty soil within the Yellow River flood area in Zhengzhou City. By considering the influence of seepage velocity at the damaged pipeline section, the study differentiates between seepage erosion and scour erosion, conducting theoretical analyses and calculations for each scenario. The results show that ① when the surrounding area of the pipeline is damaged and the slow seepage rate causes a change in the critical groundwater level ΔH ≥ (Lσt )/((1 – n)γw), the soil around the pipeline will be damaged by seep erosion; ② when the water flow velocity at the damaged area of the pipeline is reached V 0 = 2λ(γs – γw )a 2 B 2/(9μ(B 2 – b 2)), the water flow impacts the soil and causes erosion damage. The critical pressure within the pipeline can be derived from the stress state where the pipeline is damaged P1=ρ2[2λ(γs−γw)a2B2/(9μ(B2−b2))] ; ③ the underground cavity formed by water flow erosion is assumed to be an “soil arch.” The stress analysis on it obtains the critical span of the “soil arch” when the “soil arch” is damaged 2b = [2c(H + h) + Kaγ(H + h)2 tan φ – P]/(H + h/3). This study provides a theoretical basis and technical support for the management of silty ground collapse in the Yellow River flood area.

Soil structure effect on soil erosion potential

Soil erosion poses a significant threat to water-related infrastructure such as bridges, dams, quays, and levees by detaching and transporting soil grains downstream, thereby compromising the structural support of these installations. While erosion damage is acknowledged in current design practices, understanding soil erosion parameters requires scrutiny. However, existing soil erosion databases mainly rely on reconstituted soil samples, which may differ substantially from in situ erosion due to alterations in soil structure. This study scrutinizes and contrasts the erodibilities of in situ and reconstituted soils. In situ soil samples were obtained using thin-walled Shelby tubes from Victoria, Canada, while reconstituted specimens were prepared in a slurry state and consolidated to match the overburden pressure on-site. A custom rotational erosion testing apparatus facilitated erosion testing on both Shelby tube and reconstituted specimens. The findings shed light on the influence of soil fabric on soil erosion potential, an aspect currently lacking in comprehensive understanding.

Knowledge, Attitudes, and Practices of Moroccan Community Rheumatologists' Regarding the Management of Non-radiographic Axial Spondyloarthritis: A National Cross-Sectional Study.

Introduction Non-radiographic axial spondyloarthritis (nr-axSpA) is within the spectrum of axial spondyloarthritis (axSpA). The emergence of the nr-axSpA concept, defined by the absence of significant erosive damage to the sacroiliac joints, has prompted numerous initiatives aimed at enhancing the early detection and management of this condition. The aim of the study was to assess the knowledge, attitudes, and practices related to the diagnosis and management of nr-axSpA by rheumatologists in Morocco. Methods We conducted a cross-sectional online survey among the rheumatologist community in Morocco. Rheumatologists received via e-mail a structured Google Forms (Google Inc., Mountainview, CA) questionnaire divided into four sections: sociodemographic data of rheumatologists, knowledge, attitudes, and practices related to the diagnosis and treatment management of nr-axSpA. Results A total of 110 rheumatologists (mean age of 44±13 years, 77.3% females, median professional experience of 12 years (4, 75; 26.25 years)) participated in the survey (response rate of 25%). Most responders reported a diagnosis delay issue in spondyloarthritis(SpA) (93.6%); 70.9% of rheumatologists incorrectly regarded the 2009 Assessment of Spondyloarthritis International Society (ASAS) classification criteria for axSpA as diagnostic criteria. Rheumatologists' awareness of recommended magnetic resonance imaging (MRI) sequences for detecting sacroiliac joint inflammation and structural changes in SpA varied significantly, from 69.1% to 14.5%. Their knowledge of additional subchondral edema cases in these joints, beyond SpA, ranged from 48.2% to 87.3%. Almost all rheumatologists believed that the use of sacroiliac MRI would contribute to the early diagnosis of axSpA (97.3%) but could also lead to false positive diagnoses, according to 47.3% of rheumatologists; 73.6% believed that incorrectly using the 2009 ASAS classification criteria as diagnostic criteria in nr-axSpA could also result in false-positive diagnoses. In their practice, 2009 ASAS classification criteria were used as diagnostic criteria in axSpA by 39.1% of rheumatologists. Of the total participants, 91.8% indicated that they approach nr-axSpA similarly to radiographic axial spondyloarthritis, with disparities in recommendations of biological therapies. Conclusion Our survey provides insight into the current status of nr-axSpA management among Moroccan rheumatologists. It also addresses concerns regarding the risk of false positive diagnoses when using the 2009 ASAS classification criteria for axSpA as diagnostic criteria by rheumatologists and the potential risk of misdiagnosis associated with excessive reliance on MRI, despite its utility for early diagnosis.

Baffle effect of exposed WC particles in the clearance on slurry erosion behavior of cemented carbide surface

Erosion damage of clearance fits is the major factor for the failure of metal-to-metal screw motors. In this study, the slurry erosion behavior of the WC-based laser cladding layer was investigated. It aimed to explore the effect of SiO2 particle concentration on the laser cladding layer. The experimental results indicate that the WC-based laser cladding layer exhibits excellent erosion resistance across various particle concentration environments. The presence of the 'baffle effect' resulted in the cladding layer demonstrating enhanced erosion resistance, particularly at high particle concentrations. The 'baffle effect' refers to exposed WC particles hindering the movement of SiO2 particles. As SiO2 particles continuously impact the clearance material surface, much of the matrix on the cladding surface is removed. The presence of remaining WC particles on the clearance material can impede the impact of particles in the slurry. The current results aim to offer experimental support for future investigations of surface strengthening methods for metal-to-metal screw motors.

Characterization of the Dynamic Behavior of Multinanobubble System under Shock Wave Influence.

Shockwave-induced changes in nanobubbles cause cavitation erosion and membrane damage but can also be applied to biocarrier transport. Currently, research focuses on single nanobubbles; however, in reality, nanobubbles usually appear as a multibubble system. Therefore, this study proposes a method based on cutting and replicating to construct a multibubble model. This method can be widely applied to molecular dynamics (MD) models and enhance the customization capabilities of MD models. The dynamic behavior of a multinanobubble system with different numbers and arrangements of nanobubbles is investigated with the MD method under the influence of shock waves in a liquid argon system. The study also explores the range of influence between nanobubbles. The results show that in the case of two nanobubbles, when the distance between the bubbles is constant, the smaller the angle between the direction of the shock wave and the line connecting the bubbles, the greater is the influence between nanobubbles, and the moment of collapse of the nanobubbles farther away from the shock wave is slower. When three nanobubbles are arranged with a right offset, after the first bubble collapses, the effect on the other two bubbles is similar to the changes in bubbles when the angle of arrangement is 30° or 60°. Under a different arrangement, the change of shock wave velocity on the nanobubble size only affects its collapse time and contraction collapse rate. When the shock wave with a radian of about 2.87 or greater than 2.87 touches the bubbles, the collapse of the second nanobubble will not be affected.

Synovium microenvironment-responsive injectable hydrogel inducing modulation of macrophages and elimination of synovial fibroblasts for enhanced treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a progressive autoimmune disease accompanied by joint swelling, cartilage erosion and bone damage. Drug therapy for RA has been restricted due to poor therapeutic effect, recurrence and adverse effects. Macrophages and synovial fibroblasts both play important roles in the pathology of RA. Macrophages secrete large amount of pro-inflammatory cytokines, while synovial fibroblasts are tightly correlated with hypoxia synovium microenvironment, cytokine release, recruitment of pro-inflammatory cells, bone and cartilage erosion. Therefore, in this timely research, an injectable and pH-sensitive peptide hydrogel loading methotrexate (MTX) and bismuthene nanosheet/polyethyleneimine (BiNS/PEI) has been developed to reduce the activity of macrophages and eliminate over-proliferated synovial fibroblasts simultaneously. MTX can reduce the cytokine secretion of macrophages/anti-apoptosis property of synovial fibroblasts and BiNS/PEI can eliminate synovial fibroblasts via photodynamic therapy (PDT) and photothermal therapy (PTT) routes. The hydrogel was injected into the acidic inflammatory synovium for precise targeting and served as a drug reservoir for pH responsive and sustained drug release, while improving the bioavailability and reducing the toxicity of MTX. Excellent therapeutic efficacy has been achieved in both in vivo and in vitro studies, and this unique drug delivery system provides a new and robust strategy to eliminate synovial fibroblasts and modulate immune system for RA treatment in clinical.Graphic

The monocyte cell surface is a unique site of autoantigen generation in rheumatoid arthritis

Although anti-citrullinated protein autoantibodies (ACPAs) are a hallmark serological feature of rheumatoid arthritis (RA), the mechanisms and cellular sources behind the generation of the RA citrullinome remain incompletely defined. Peptidylarginine deiminase IV (PAD4), one of the key enzymatic drivers of citrullination in the RA joint, is expressed by granulocytes and monocytes; however, the subcellular localization and contribution of monocyte-derived PAD4 to the generation of citrullinated autoantigens remain underexplored. In this study, we demonstrate that PAD4 displays a widespread cellular distribution in monocytes, including expression on the cell surface. Surface PAD4 was enzymatically active and capable of citrullinating extracellular fibrinogen and endogenous surface proteins in a calcium dose-dependent manner. Fibrinogen citrullinated by monocyte-surface PAD4 could be specifically recognized over native fibrinogen by a panel of eight human monoclonal ACPAs. Several unique PAD4 substrates were identified on the monocyte surface via mass spectrometry, with citrullination of the CD11b and CD18 components of the Mac-1 integrin complex being the most abundant. Citrullinated Mac-1 was found to be a target of ACPAs in 25% of RA patients, and Mac-1 ACPAs were significantly associated with HLA-DRB1 shared epitope alleles, higher C-reactive protein and IL-6 levels, and more erosive joint damage. Our findings implicate the monocyte cell surface as a unique and consequential site of extracellular and cell surface autoantigen generation in RA.

Fibrous Solar Evaporator with Tunable Water Flow for Efficient, Self‐Operating, and Sustainable Hydroelectricity Generation

AbstractConvenient and green hydroelectricity generation (HG) systems are widely studied to cope with the energy crisis. Electricity can be generated through streaming potential with merely water droplets. Nevertheless, the operational requirement of persistent water supply restricts the durability and practicality of HG. Solar‐driven steam generation with continuous and sufficient water flow has become a promising integration way to enhance HG sustainability. However, most evaporation‐accelerated hydroelectricity generators are threatened by excessive wetting decay and ionic erosion damage, which significantly impair charge accumulation and operational durability. To address this issue, a carbon black/polypyrrole decorated Tencel framework (CPF) with tunable water flow is fabricated through twisting and braiding technology. The modified water flow rate, height, and content ensure rapid ion migration, appropriate wetting boundary, and sufficient brine circulation, respectively. The aqueous flow and ion strength are optimized through the evaporation‐accelerated and desalination‐integrated HG. Hence, the CPF evaporator shows an efficient, self‐operating, and sustainable output of 0.73 V, 0.6 µA, and 2.38 kg m−2 h−1 in 3.5 wt.% brine under 1 sun radiation without salt deposition. The scalable, prolonged, and adaptable outdoor operation throughout the daytime ensures the clean production of electricity and freshwater.

Nonlinear response to contact impact on the surface of an aluminum alloy AlMg6 exhibiting the Portevin-Le Chatelier effect

Intermittent plastic flow known as the Portevin-Le Chatelier effect is a pronounced nonlinear phenomenon in a material science. One of the traditional approaches to the study of nonlinear system is to identify and analyze its responses to an external impulsive action. In the present work, the influence of impact indentation on the evolution of the spatio-temporal patterns of localized strain in an AlMg alloy deformed under the Portevin-Le Chatelier effect is studied with using an acoustic emission technique and high-speed video recording of propagating deformation bands. Dynamic and nonlinear responses to impact indentation of the surface of an alloy deformed by uniaxial tension above the conditional yield strength are revealed; the first include high values of dynamic hardness and local strain and loading rates, while the second involve the threshold and multiple nature of the force and acoustic responses. It has been established that there is a threshold impact energy of the indenter at which an induced strain jump of minimum amplitude occurs, accompanied by the formation of bands of macrolocalized plastic deformation. The conditions are established under which the work of plastic deformation during the development of the induced strain jump significantly, by more than two orders of magnitude, exceeds the energy of the initiating impact, which acts only as a trigger for the “premature” release of the elastic energy accumulated in the material before the moment of impact. It is shown that the impact-induced bands of macrolocalized deformation represent a hidden three-dimensional type of erosion damage that reduces the mechanical stability and durability of the alloy. A phenomenological model is proposed for the formation of bands, strain jumps, and bursts of acoustic emission induced by an indenter impact, which qualitatively explains the experimental results obtained in the work.

Enhanced YOLO v3 for precise detection of apparent damage on bridges amidst complex backgrounds

A bridge disease identification approach based on an enhanced YOLO v3 algorithm is suggested to increase the accuracy of apparent disease detection of concrete bridges under complex backgrounds. First, the YOLO v3 network structure is enhanced to better accommodate the dense distribution and large variation of disease scale characteristics, and the detection layer incorporates the squeeze and excitation (SE) networks attention mechanism module and spatial pyramid pooling module to strengthen the semantic feature extraction ability. Secondly, CIoU with better localization ability is selected as the loss function for training. Finally, the K-means algorithm is used for anchor frame clustering on the bridge surface disease defects dataset. 1363 datasets containing exposed reinforcement, spalling, and water erosion damage of bridges are produced, and network training is done after manual labelling and data improvement in order to test the efficacy of the algorithm described in this paper. According to the trial results, the YOLO v3 model has enhanced more than the original model in terms of precision rate, recall rate, Average Precision (AP), and other indicators. Its overall mean Average Precision (mAP) value has also grown by 5.5%. With the RTX2080Ti graphics card, the detection frame rate increases to 84 Frames Per Second, enabling more precise and real-time bridge illness detection.

Study on Dynamic Evolution and Erosion Characteristics of Cavitation Clouds in Submerged Cavitating Water Jets

The dynamic evolution behavior of submerged water jet cavitation clouds was studied by combining experiments and simulation. The formation, development, shedding, and collapsing process of a void cloud was analyzed by high-speed camera technology, and the influence of jet pressure was studied. Cavitation water jet erosion experiments were carried out on AL6061 specimens with standard cylindrical nozzles, and the correlation between cavitation cloud evolution and material erosion was studied by surface analysis. The results showed that the evolution of a cavitation cloud has obvious periodicity, that one period is about 0.8 ms, and its action region can be divided according to the attenuation rate of the jet velocity of the nozzle axis. The attenuation rate of the jet velocity at the nozzle axis in the central jet action zone is less than or equal to 82.5%, in the mixed action zone greater than 82.5% and less than 96%, and in the cavitation action zone greater than or equal to 96%. The erosion damage characteristics in different regions of the mixed action zone are significantly different.

Calibration of Oil Film Thickness Acoustic Reflection Coefficient of Bearing under Multiple Temperature Conditions

Rolling mill bearings are prone to wear, erosion, and other damage characteristics due to prolonged exposure to rolling forces. Therefore, regular inspection of rolling mill bearings is necessary. Ultrasonic technology, due to its non-destructive nature, allows for measuring the oil film thickness distribution within the bearing during disassembly. However, during the process of using ultrasonic reflection coefficients to determine the oil film thickness and distribution state of rolling mill bearings, changes in bearing temperature due to prolonged operation can occur. Ultrasonic waves are susceptible to temperature variations, and different temperatures of the measured structure can lead to changes in measurement results, ultimately distorting the results. This paper proposes using density and sound speed compensation methods to address this issue. It simulates and analyzes the oil film reflection coefficients at different temperatures, ultimately confirming the feasibility and effectiveness of this approach. The paper establishes a functional relationship between bearing pressure and reflection coefficients, oil film thickness, and reflection coefficients. This allows for the compensation of reflection coefficients under any pressure conditions, enhancing the accuracy of oil film thickness detection. The proposed method provides technical support for the maintenance of plate rolling processes in the steel industry.

Randomised nano-/micro- impact testing – A novel experimental test method to simulate erosive damage caused by solid particle impacts

A novel randomised nano-/micro-scale impact test method has been developed to experimentally simulate particulate erosion where statistically distributed impacts with defined energy occur sequentially within the test area. Tests have been performed on two brittle glasses (fused silica and BK7) to easily highlight the interaction between impacts, as well as on two ceramic thermal barrier coating systems (TBCs, yttria stabilised zirconia, 7YSZ, and gadolinium zirconate, GZO) that experience erosion in service. Differences in erosion resistance were reproduced in the randomised impact tests, with GZO less impact resistant than 7YSZ, and BK7 significantly worse than fused silica. The impact data show that erosion resistance is influenced by different factors for the glasses (crack morphology, longer-length interaction of radial-lateral cracks in BK7 vs cone-cracking in fused silica) and TBCs (fracture toughness).

Simulation of cavitation erosion damage and structural evolution caused by nano-bubbles for iron

In this work, the dynamic behavior of nano-bubbles near the surface of single crystal iron (Fe) was investigated using molecular dynamics simulations. The cavitation erosion behavior of single crystal Fe and the structural evolution of its eroded surface was examined at different bubble diameters. The results show that nano-bubble diameter is inversely correlated with impact pressure and diameter is positively correlated with nanojet energy. The volume, surface area, and depth of cavitation pits are nearly directly proportional to the bubble diameter with correlation linear fitting coefficients of R2 = 0.9837, R2 = 0.9922, and R2 = 0.9799, respectively. Additionally, cavitation erosion induces the structural evolution of iron atoms from bcc to fcc and hcp structures. The percentage of new phase transformed is related to the bubble diameter and the type of transformed structure, the percentage of fcc and hcp structures of Fe atoms exhibits an increasing trend with the increase in the bubble diameter, and the Fe atoms of fcc structures occur an obvious increase beyond a bubble diameter of 12 nm.

Damage evolution of CFRP laminates by normal and oblique impact erosion of pulsating water jets

Impact direction is one of the critical factors affecting the waterdrop erosion behavior of materials. In this paper, rain erosion damage behavior of a typical carbon fiber reinforced polymer (CFRP) laminate is investigated as a function of the impingement angle (0° as normal impact and 15°, 30°, 45° as oblique impact deviated from the normal) and the relative fiber orientation (parallel PA and perpendicular PE to the fiber direction of the surface layer) under the waterjet velocity of 320 m/s and the impact frequency of 50 Hz via a pulsating waterjet erosion test rig. After continuous impact of multiple waterjets, the typical damage of CFRP laminates is mainly composed of the central erosion crater and the upheaval of the surrounding surface layer. The onset and evolution of damage are mainly driven by the shear action of lateral jetting and stress concentration of hydraulic penetration exerted at the surface irregularities. There is no significant difference in the damage modes between the normal and oblique impacts, except for the asymmetric distributions of matrix cracking in PA-orientation and delamination in PE-orientation caused by the angle inclination. With the impingement angle increasing, the volume loss and erosion depth decrease while the incubation period increases mainly due to the decreases of water hammer pressure and contact area. The PA-orientation can cause lower incubation period and larger erosion mass loss than PE-orientation before the surface ply is penetrated, with the underlying mechanism related to the distinct tensile properties of CFRP laminates along longitudinal and transversal directions and the asymmetric properties of fiber–matrix interface. According to the fitting results of erosion curves, it is possible to describe the incubation period and the erosion rate of CFRP laminates under oblique impact using a two-branch equation, and Springer model can give reasonable prediction for the average incubation period and PA-orientation erosion rate of a certain oblique impact occasion with known 0° impact erosion results.

Research on the solid particle erosion wear of pipe steel for hydraulic fracturing based on experiments and numerical simulations

Erosion wear is a common failure mode in the oil and gas industry. In the hydraulic fracturing, the fracturing pipes are not only in high-pressure working environment, but also suffer from the impact of the high-speed solid particles in the fracturing fluid. Beneath such complex conditions, the vulnerable components of the pipe system are prone to perforation or even burst accidents, which has become one of the most serious risks at the fracturing site. Unfortunately, it is not yet fully understood the erosion mechanism of pipe steel for hydraulic fracturing. Therefore, this article provides a detailed analysis of the erosion behavior of fracturing pipes under complex working conditions based on experiments and numerical simulations. Firstly, we conducted erosion experiments on AISI 4135 steel for fracturing pipes to investigate the erosion characteristics of the material. The effects of impact angle, flow velocity and applied stress on erosion wear were comprehensively considered. Then a particle impact dynamic model of erosion wear was developed based on the experimental parameters, and the evolution process of particle erosion under different impact angles, impact velocities and applied stress was analyzed. By combining the erosion characteristics, the micro-structure of the eroded area, and the micro-mechanics of erosion damage, the erosion mechanism of pipe steel under fracturing conditions was studied in detail for the first time. Under high-pressure operating conditions, it was demonstrated through experiments and numerical simulations that the size of the micro-defects in the eroded area increased as the applied stress increased, resulting in more severe erosion wear of fracturing pipes.

Experimental analysis and model prediction of elbow pipe's erosion in water-cooled radiator

The radiator with heat transfer capability is able to guarantee the stable operation of hydro generator set, while the long-term and continuous scouring on radiator pipes by cooling medium will lead to thinning or even perforation of pipe wall, which triggers wall failure. This paper analyzes and predicts the failure mechanism of radiator’s pipe wall, and investigates the effects of water flow velocity, sand content and sand particle size on erosion damage of radiator pipe by establishing a test bench for pipe erosion. The results show that the increase of above parameters will lead to the increasing erosion rate, especially when the sand content is 1%, the velocity is 8 m/s and the sand particle size is 0.85 mm, the erosion damage will be particularly serious. Based on experimental data, BP and LSSVM models are employed to predict the pipe wall failure, and PSO algorithm is used to optimize the two models. The optimized PSO-BP has the highest accuracy with the mean absolute error (MAE) of 0.2070 and the mean absolute percentage error (MAPE) of 4.702%. The findings provide a reference for wall failure analysis of radiator, which is of great significance for unit's safe operation.

An investigation on the effect of heat input to wear behavior and corrosion-cavitation erosion mechanism of Hastelloy C-276 coating by cold metal transfer

Cold metal transfer (CMT) technology based on wire-arc manufacturing has attracted wide attention because of its advantages of high manufacturing efficiency, low heat input (HI) and near-net-shape. In this study, a CMT-Hastelloy C-276 superalloy surface modification coating by optimizing HI is used to solve the problem of premature failure of key over-flow components of stainless steel in marine engineering. When the HI is increased from 269 J/mm to 358 J/mm, the serious cavitation erosion (CE) damage caused by pore defects and excessive residual tensile stress due to excessive low HI of Hastelloy C-276 coating can be avoid, which is attributed to the effective Orowan strengthening and high proportion of low angle grain bounds (LAGBs: 70.2%). In addition, high contents of Cr, Mo and W elements can promote it's passivation film to maintain excellent self-healing ability during CE to provide continuous and stable protection effect (Rct = 75.68 kΩ·cm2) in the 3.5 wt% NaCl artificial seawater. Therefore, even after 10 h-CE, it still maintains the highest corrosion resistance from both of the thermodynamic (Ecorr = −193.5 ± 3.6 mV) and kinetic perspective (Icorr = 69.3 ± 3.1 μA·cm−2) and has the lowest mean depth erosion rates (MDER, 0.94 ± 0.07 μm/h). However, further increase of HI will cause coarsing of grains (89.6 ± 2.7 μm → 342.8 ± 9.7 μm), excessive precipitation of brittle Mo-rich p phase and excessive dilution of elements from the substrate, resulting in changes in the wear mechanism and deterioration of strength and corrosion resistance. Moreover, the potential of zero charge (PZC) measurements and Mott-Schottky (M-S) test confirmed the decreasing trend of the repulsive ability to Cl ions (ΔE = 0.58 V) and the increased ion doping concentration (ND = 5.94 ± 0.02 × 1022 cm−3) of the weakened n-type passivation films. The optimal combination of wear resistance, corrosion resistance and CE resistance of Hastelloy C-276 coating is obtained by regulating HI, which can lay a theoretical foundation for the related production and application of marine engineering.

Concomitant Sjögren’s disease as a biomarker for treatment effectiveness in rheumatoid arthritis - results from the Swiss clinical quality management cohort

ObjectiveTo investigate the clinical phenotype and treatment response in patients with rheumatoid arthritis (RA) with and without concomitant Sjögren’s disease (SjD).MethodsIn this observational cohort study, patients with RA from the Swiss Clinical Quality Management in Rheumatic Diseases registry were categorised according to the presence or absence of SjD. To assess treatment effectiveness, drug retention of tumor necrosis factor-α-inhibitors (TNFi) was compared to other mode of action (OMA) biologics and Janus kinase-inhibitors (JAKi) in RA patients with and without SjD. Adjusted hazard ratios (HR) for time to drug discontinuation were compared in crude and adjusted Cox proportional regression models for potential confounders.ResultsWe identified 5974 patients without and 337 patients with concomitant SjD. Patients with SjD were more likely to be female, to have a positive rheumatoid factor, higher disease activity scores, and erosive bone damage. For treatment response, a total of 6781 treatment courses were analysed. After one year, patients with concomitant SjD were less likely to reach DAS28 remission with all three treatment modalities. Patients with concomitant SjD had a higher hazard for stopping TNFi treatment (adjusted HR 1.3 [95% CI 1.07–1.6]; OMA HR 1.12 [0.91–1.37]; JAKi HR 0.97 [0.62–1.53]). When compared to TNFi, patients with concomitant SjD had a significantly lower hazard for stopping treatment with OMA (adjusted HR 0.62 [95% CI 0.46–0.84]) and JAKi (HR 0.52 [0.28–0.96]).ConclusionRA patients with concomitant SjD reveal a severe RA phenotype, are less responsive to treatment, and more likely to fail TNFi.