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• The failure analysis of 6 welded joints with cracks excavated on site in a gas transmission company was carried out. • The relationship between root welding, weld microstructure and crack generation was clarified. • The influence mechanism of grain boundary distribution and inclusions on crack propagation path in weld microstructure was revealed. The girth weld is the weak link of high-pressure pipeline, which is easy to crack under the combined action of internal and external loads, defect and stress concentration. At present, the safety hazards of high-strength pipeline girth welds are prominent, and it is of great significance to study the failure law of girth welds to ensure the safe operation of pipelines. In this paper, the failure analysis of 6 welded joints with crack defects excavated on site in a gas transmission company was carried out. Through metallographic analysis, scanning electron microscope (SEM) observation and electron backscatter diffraction (EBSD) analysis, the relationship between root welding, weld microstructure and crack generation was analyzed in detail. The influence of grain boundary distribution behavior of weld microstructure on crack propagation path was studied, and the mechanism of welding inclusions on crack propagation and aggregation nucleation was revealed. The results show that the cracks in root welding, hot welding, filling welding and heat affected zone are all transgranular propagation types, and the deflection of crack propagation path may be related to the complex stress state at the welded joint. Local strain concentration often exists in the near crack surface, secondary crack and crack deflection position on the crack propagation path, which indicates that the formation and propagation of root cracks are likely to be related to the deterioration of weld metal properties caused by local strain concentration at the root. The research conclusions have certain reference value for the intrinsic safety design, construction, and integrity operation and maintenance of pipeline girth welds. [ABSTRACT FROM AUTHOR]

Abstract A number of evidences suggest that microRNAs are involved in the adipogenic commitment of mesenchymal stem cells (MSCs). Recent studies have investigated that miR-199a-3p played a pivotal role in adipocyte differentiation. However, the detailed mechanism in this complex biological process remains largely unknown. In current study, we found that the expression of miR-199a-3p was gradually increased during adipogenic differentiation of bone marrow derived mesenchymal stem cells (BMMSCs). Enhanced expression of miR-199a-3p promoted adipogenesis, whereas silence of miR-199a-3p rescued BMMSCs from adipogenic commitment. For further mechanism exploration, KDM6A was confirmed to be the target of miR-199a-3p and the expression of KDM6A was gradually decreased during adipogenic differentiation of BMMSCs. Furthermore, up-regulation of KDM6A markedly abolished the miR-199a-3p overexpression induced adipogenic augmentation, whereas down-regulation of KDM6A suppressed the adipogenic reduction caused by miR-199a-3p silence. In addition, WNT signaling was also verified to be the downstream of miR-199a-3p/KDM6A to regulate adipogenic differentiation of BMMSCs. Taken together, current results indicate that miR-199a-3p regulate adipogenesis of BMMSCs by targeting KDM6A/WNT signaling, which highlights a new insight for a better understanding of molecular mechanism and stem cell based therapy on osteoporotic diseases. [ABSTRACT FROM AUTHOR]

Rechargeable lithium-sulfur (Li-S) batteries are considered as one of the most potential energy storage devices owing to their high theoretical capacity, environmental friendliness and low cost. However, the practical applications of Li-S batteries are restricted by the low conductivity of sulfur, serious dissolution of intermediate polysulfides and fast capacity degradation. Herein, we design a titanium nitride (TiN) modified separator to improve the long-term cycle stability and discharge capacity of Li-S batteries. Strong interaction between the TiN particles and polysulfides can greatly restrain the “shuttle effect” and benefit the cycle stability. With this modified separator, cathodes with a sulfur loading of 78.1% could deliver a high initial discharge capacity of 1296 mAh/g and demonstrate a decay rate of 0.17% per cycle under a high current density of 0.5C. Such superior electrochemical performances ascribe to the high conductivity of TiN and strong affinity between TiN particles and polysulfides. [ABSTRACT FROM AUTHOR]

Three kinds of carbon-modified electrodes on stability of lithium metal deposition were investigated. Results indicated the amorphous carbon-modified electrode is more effective to improve initial Coulombic efficiency than the graphitized carbon-modified electrode. With high porosity (81%) and amorphous crystal structure, the low cost micro-hollow carbon fiber foam electrode provides high and stable Coulombic efficiency of 99.5% for more than 100 cycles when the areal capacity of electrode approaches 6 mAh·cm −2 . The high areal capacity of high porosity electrode would be a promising anode for lithium-sulfur battery. [ABSTRACT FROM AUTHOR]

The paper provides a new model to predict the burst pressure for corroded pipeline by finite element method. Error analysis with commonly used models shows that the new model has better prediction precision. Based on this model, the limit state equation is established and numerically solved by using Monte Carlo Simulation (MCS). It shows that the new model is feasible for reliability analysis of corroded pipelines when compared with other widely used models. The sensitivity analysis of parameters and model revealed that the corrosion depth and the pipeline operation pressure have the most influence on the pipeline failure probability. [ABSTRACT FROM AUTHOR]

Most of the commonly used standards and codes for burst pressure prediction at a corrosion defect of steel pipelines generally just consider internal pressure alone. However, an actual oil/gas pipeline is usally subjected to external loads, such as axial compression/tension and bending moment, which may affect the burst capacity of the pipeline. In this study, a three-dimensional (3D) nonlinear finite element (FE) model validated by burst tests was developed to investigate the effect of bending moment and axial force on the burst capacity of corroded pipelines. Subsequently, the effects of external loads (i.e., bending moment, and axial force) and corrosion geometry features (involving corrosion depth, width, length, and clock position) on the pipe burst pressure were determined. Then, based on a series of FE cases, a new burst prediction model for corroded pipelines subjected to the combination loads of bending load and axial compressive force was fitted and developed. Finally, the effectiveness and reliability of the new proposed model were verified by extensive parametric FE analysis and burst test data. The results show that the prediction errors for the failure pressures between the proposed-model and the FEM were less than 10% for most 92.793% of the 222 cases. Moreover, the proposed model can also be applied to the condition that the pipeline is under single internal pressure, and its prediction accuracy is better than that of other seven well-known models of ASME B31G, Mod B31G (0.85 d L), Z662, DNV, PCORRC, CUP, and Shell-92. • Developed a finite element model for corrosion defect assessment on pipeline under bending moment and axial force. • Determined the effect of corrosion width on failure pressure of pipelines. • Considered the effect of clock position of corrosion defect on burst pressure of pipelines. • Proposed a novel burst capacity model for corroded pipelines under bending and axial compression loads. • Determined the effect of bending moment and axial force on failure pressure of corroded pipelines. [ABSTRACT FROM AUTHOR]

Burst capacity assessment at a corrosion defect of pipe elbows subjected to internal pressure is essential for oil/gas pipeline integrity management. In this study, a three-dimensional (3D) nonlinear finite element (FE) model validated by burst tests was developed to investigate the effect of corrosion defects on the burst capacity of X80 pipe elbows. Subsequently, the effects of corrosion geometry (i.e. depth, length, and width of the defect) on the pipe burst pressure were determined. Based on the Goodall model of intact pipe elbows, a reasonable mathematical expression for the failure pressure prediction formula for corroded pipelines under external loads was derived by introducing a defect geometry factor function. Then, combined with a series of FE cases, a new prediction model of burst pressure for corroded pipe elbows experiencing internal pressure was developed. Finally, the accuracy and reliability of the proposed model were verified using extensive parametric FE analysis. The results show that the average error of failure pressure between the proposed model and FEM was only 3.63% for 291 cases. Moreover, the prediction accuracy was better than other well-known models. Therefore, the proposed model can be widely used in the safety assessment of corroded elbows of oil/gas pipelines. • A novel model for predicting the ultimate burst capacity of corroded pipe elbows. • A finite element model for burst analysis on corroded elbows. • Determined the failure pressure of pipe elbows containing a corrosion defect. • Dependence of the burst capacity of elbows on corrosion defect geometry. [ABSTRACT FROM AUTHOR]

A dent is a typical defect found in oil and gas pipelines and poses a significant threat to their safety and integrity. In this study, the buckling behavior and limit strain capacity of pipelines with kinked dents under bending moment loads were investigated. First, four-point bending tests of full-scale pipelines with kinked dents were conducted in a laboratory, and the critical buckling load and strain response of the pipelines during buckling failure were tested. The test results revealed that the existence of kinked dents, specifically those with large depths, could weaken the bending resistance of the pipelines. During the buckling process of the pipeline, a considerable compressive strain was generated at the bottom center of the dent, which was considerably higher than the strain value at the corresponding position of the intact pipeline. However, the strain at both axial sides of the dent gradually changed from compressive strain at the initial bending stage to tensile strain after buckling failure. Then, nonlinear finite element (FE) models of buckling failure for pipelines with kinked dents under bending moment loads were developed, and the reliability of the FE models was verified through comparison with the test results. In addition, a parametric sensitivity study was conducted to determine the effect of parameters, such as dent depth, dent angle, diameter-to-thickness ratio of the pipe, and yield ratio of the pipe steel, on the compressive strain capacity of the pipeline. Finally, based on a large number of FE simulation results, a model for predicting the buckling compressive strain capacity of pipelines with kinked dents was developed, which can be used for evaluating buckling instability failure of pipelines with kinked dents subjected to bending moment loads. • A strain-based assessment method for dented pipelines under bending loads. • A finite element model for buckling analysis on dented pipeline. • A bending test of buckling failure of pipelines with kinked dents. • Dependence of the compressive strain capacity on pipe geometry and steel material. • The critical compressive strain of buckling as a function of dent depth, angle. [ABSTRACT FROM AUTHOR]

Abstract: Increasing evidence from in vivo and in vitro studies has indicated that MT exerts protective effects against DOX-induced cardiotoxicity; however the underlying precise mechanisms still remain an enigma. Therefore, the present study was designed using MT knockout mice in concert with genomic approaches to explore the possible molecular and cellular mechanisms in terms of the genetic network changes. MT-I/II null (MT−/−) mice and corresponding wild-type mice (MT+/+) were administrated with a single dose of DOX (15mg/kg, i.p.) or equal volume of saline. Animals were sacrificed on the 4th day after DOX administration and samples were collected for further analyses. Global gene expression profiles of cardiac mRNA from two genotype mice revealed that 381 characteristically MT-responsive genes were identified between MT+/+ mice and MT−/− mice in response to DOX, including fos, ucp3, car3, atf3, map3k6, etc. Functional analysis implied MAPK signaling pathway, p53 signaling pathway, Jak-STAT signaling pathway, PPAR signaling pathway, Wnt signaling pathway, etc. might be involved to mediate the protection of DOX cardiomyopathy by MT. Results from the present study not only validated the previously reported possible mechanisms of MT protection against DOX toxicity, but also provided new clues into the molecular mechanisms involved in this process. [Copyright &y& Elsevier]

This work presents an investigation on the compressive strain capacity of resisting buckling on an X80 steel corroded pipeline subjected to a bending moment using nonlinear finite element analysis (FEA) validated by full-scale tests. The modelling results indicate that the existing strain-based assessment method is not suitable for pipelines with deep corrosion and has certain application limitations. Consequently, a new evaluation method based on far-field strain was developed to predict the buckling failure of corroded pipelines subjected to bending loads. The influence of the corrosion shape type, corrosion size (i.e., depth d , length L , and width w), pipe geometry, and internal pressure on the critical buckling strain capacity and critical buckling moment of the pipeline were studied using parameter sensitivity analysis to verify the proposed strain criteria. The results illustrate that the variation trends between the critical buckling strain and the critical buckling moment with each factor were consistent, indicating that the proposed novel strain-based evaluation method is effective and applicable. In addition, the buckling resistance of a pipeline with rectangular corrosion is relatively weaker than that with a semi-spherical corrosion pit or cylindrical grooved corrosion under the same defect size. Further, the critical compressive strain capacity of a corroded pipeline is primarily affected by the depth and width of the corrosion, whereas the effect of the corrosion length is relatively insignificant. Moreover, the critical length and width of the corrosion defect affecting the bending capacity of resisting buckling were determined as L / D t = 20 and w / π D = 0. 5 , respectively. • A novel strain-based assessment method of local buckling of corroded pipelines. • Determined the effect of defect geometry on critical compressive strain capacity. • Determined the critical defect size that affect the pipe buckling strain capacity. [ABSTRACT FROM AUTHOR]

Dents have been identified as among the most common deformation defects in oil and gas pipelines. In this study, the multidimensional mechanical responses, springback, and rerounding behaviors of dents as well as the interaction of multiple dents on pipelines and their effect on pipe integrity were investigated through the three-dimensional finite element method and full-scale burst tests. The burst test demonstrates that a plain dent has a minimal effect on the pipeline burst pressure, and the burst failure position is not located in the dented area. Generally, when a dented pipeline that is subjected to monotonically increasing internal pressure bursts, the dent does not fully reround, and a convex protuberance forms in the axial shoulders on both sides of the dent. During pressurization, the maximum equivalent plastic strain in the dented pipe always occurs on the inner surface near the dent center in which no necking is found in the radial direction of the wall thickness. However, a larger equivalent stress is observed around the edge of the dent center, whereas the stress at the center is relatively small, resulting in the formation of a plastic hinge in the dented area. If internal pressure fluctuations occur, this can easily lead to fatigue failure. Finally, the interaction among multiple longitudinally aligned dents was investigated, and the critical spacing affecting the integrity of the pipeline was determined. The investigation reveals that when the dent spacing exceeds the pipe diameter, the interaction between two dents may be ignored, and the dent effect on the pipe integrity may be separately evaluated. However, if the dent spacing is less than 0.5 times the pipe diameter, then the dents must be treated as a combined dent. Further, if the spacing is 0.5–1.0 times the pipe diameter, then dent interaction must be considered. • Developed a finite element model to assess the integrity of pipelines with multiple longitudinally aligned dents. • The edges of the dent center show highly strain sensitivity to the variations of internal pressure. • API 579 suggests the empirical value of rebound coefficient at 1.43 may lead to non-conservative result. • A circle of plastic hinge was observed around the dent which may cause fatigue of pipe material. • The critical spacing distance of interaction between multiple longitudinally aligned dents on pipelines was determined. [ABSTRACT FROM AUTHOR]

The assessment of corrosion defects to determine their effect on pipeline integrity is essential for pipe managers to develop a scientific maintenance strategy. In this work, a nonlinear finite element (FE) model coupled with multi-physical fields was developed to study the mechano-electrochemical (M-E) synergistic effect at an external corrosion defect on X100 pipeline elbow. The results indicated that bending radius has an apparent effect on the burst pressure of the corroded pipe elbow. However, anodic and cathodic reactions was insensitive to bending radius under normal working pressures. Pipes elbows with corrosion defects located in the intrados have a lower burst pressure than those in the extrados and central line crowns. When the deformation or stress generated at the corrosion defect was elastic, the synergistic mechano-electrochemical interaction effect was insignificant. However, when the depth of the defect or the applied internal pressure of the elbow was sufficient to produce a local plastic strain in the corroded region, the corrosion reaction of the local steel at the defect was remarkably enhanced. Under multiaxial stress, the corrosive behaviour of steel in the defective area involved numerous local galvanic batteries, with the anode located in the high-stress zone and the cathode in the lower-stress zone. Anodic polarisation was found to occur in high-stress zone, which accelerated local corrosion. • Developed a finite element model for corrosion defect assessment on pipe elbows. • Determined the failure pressure of pipe elbows containing a corrosion defect. • The location of the defect on an elbow affects the burst pressure of the pipeline. • The defect depth affects the local stress and anodic current density distributions. • The internal pressure affects the stress and anodic current density at the defect. [ABSTRACT FROM AUTHOR]

Abstract: Metallothionein (MT) has been shown to be an effective protector against DOX-induced cardiomyopathy, however the involved precise mechanisms are still unknown. The present study was undertaken to clarify whether the inhibition of superoxide generation and related nitrosative damage were involved in the metallothionein attenuation of DOX-induced cardiac injury. MT-I/II null (MT−/−) mice and corresponding wild-type mice (MT+/+) were pretreated with either saline or zinc (300μmol/kg, s.c., once a day for 2 days) prior to a single dose of DOX (15mg/kg, i.p.) or equal volume of saline. Animals were sacrificed on the 4th day after DOX administration and samples were collected for further analyses. DOX caused remarkable cardiac damage in both MT+/+ and MT−/− mice as demonstrated by biochemical and histopathological alterations. Zinc pretreatment significantly increased the cardiac MT levels and therefore inhibited the cardiac toxic effects of DOX only in MT+/+ mice, but not in MT−/− mice. Furthermore, elevated formation of superoxide and peroxynitrite were obviously observed after DOX treatment, while these elevation were prevented by MT induction by zinc in MT+/+ mice, but not in MT−/− mice. These findings suggest that metallothionein induction by zinc exhibits protective effects on the cardiac toxicology of DOX, which might be mediated through the prevention of superoxide generation and related nitrosative impairment. [Copyright &y& Elsevier]

This work investigated stress response of a corroded X80 steel pipeline repaired by a type-B sleeve to internal pressure by finite element modeling. Firstly, a three-dimensional numerical model of corroded pipeline reinforced with type-B sleeve was developed, and its accuracy and reliability were verified by the burst test results and the theoretical analytical solution, respectively. Second, the von Mises stress of the pipe body, sleeve and fillet weld was simulated under various affecting factors, i.e., internal pressure, corrosion defect dimension (depth, length and width) and sleeve length. Finally, a parameter sensitivity study was conducted to determine the effects of corrosion geometry and sleeve length on the repair efficiency. The main investigation results show that the type-B sleeve repair method is effective to restore the pressure-bearing capacity of the pipeline at the corrosion defect, and the burst failure of repaired pipeline always occurs at the region far away from the defect and sleeve. At the limit state of burst, the local defective region shows the highest stress, followed by the fillet weld, and the repair sleeve has the smallest stress, thus the maximum equivalent stress of the corroded zone is suggested to be used for measuring the repair efficiency of the repaired pipe by type-B sleeve. The sleeve-repair effectiveness is affected by depth of the corrosion defect, a deep corrosion defect reduces the performance of the sleeve repair compared with a shallow defect. The effect of the corrosion defect length on sleeve repair depends on the defect depth. Furthermore, there exist a critical length of the defect that affect the repair efficiency. The corrosion defect width shows limited effect on stress level at the defect of the repaired pipe. At last, a new method based on stress analysis is proposed to optimize the sleeve length for repairing a corroded pipeline. • A FE model for mechanical analysis on a corroded pipeline reinforced with sleeve. • An assessment method of repairing effect of type-B sleeve repair pipeline. • The stress distribution of repaired pipe body, sleeve and fillet weld was determined. • Proposed a new method to select optimal sleeve length for pipeline repair. • Determined the effect of defect geometry on sleeve repair performance. [ABSTRACT FROM AUTHOR]

• Sulfurized polyacrylonitrile prepared by diphenyl guanidine vulcanization accelerator significantly enhances discharge capacity and cycling stability. • Diphenyl guanidine dramatically improves the sulfur content of sulfurized polyacrylonitrile by 14 wt%. • Sulfurized polyacrylonitrile cathode prepared by diphenyl guanidine vulcanization accelerator delivers 897 mA h gcomposite-1 cathodic capacities corresponding Li-S batteries. A comparative study on the effect of different vulcanization accelerators on the electrochemical performance of sulfurized polyacrylonitrile cathodes is conducted for the first time. Compared with these vulcanization accelerators, the sulfurized polyacrylonitrile composite prepared by diphenyl guanidine vulcanization accelerator significantly enhances discharge capacity and cycling stability. Diphenyl guanidine dramatically improves the sulfur content by 14 wt%, resulting in a remarkable discharge capacity of 897 mA h g composite −1 at a rate of 0.1C (1C = 700 mA g−1) corresponding Li-S batteries, while maintain the outstanding cycling stability. Therefore, diphenyl guanidine can be used as a vulcanization accelerator in the formulation of a high-capacity sulfurized polyacrylonitrile cathodes. [ABSTRACT FROM AUTHOR]

As the main geometric defect in pipeline maintenance, dent has been paid more attention by pipeline managers because of its strong stress concentration. To investigate the formation mechanism of a pipeline dent, an indentation test of a pipe subjected to concentrated lateral load was carried out in the laboratory to simulate the formation process of the dent, and a 3D numerical model corresponding to the test was established to verify the results between the experiment and simulation. Subsequently, the stress and strain response of the dented pipeline was analyzed in detail in various stages of dent formation process. Deformation analysis revealed that the residual stresses state formed in the dented area after unloading is related to the depth of the dent, which may be in tension or in compression. During the formation of the dent, the pipeline presents "∽"-type wave-like bending state in the axial direction. These dent formation mechanisms may provide a guidance for dent assessment studies. [ABSTRACT FROM AUTHOR]

Highlights • Injecting liquid KNa alloy into sandwich-like carbon felt at room temperature. • Synthesizing nano-scale SPAN via a one-step facile solid state reaction. • The new battery presents good cycle stability (capacity retention 95.5%/100 cycles). Abstract Considering high earth abundance and low cost of potassium resource, potassium ion batteries are very promising candidates for energy storage devices due to its similar electrochemical performance to lithium ion batteries and more negative potential than sodium anode. K–Na alloy extending from 41.8 to 90.8 wt% potassium is liquid at ambient temperature. It was used as anode for a rechargeable potassium–sulfur battery in this work because of its high capacity and dendrite-free when charging and discharging. Sulfurized polyacrylonitrile (SPAN) nanocomposites were synthesized and adopted as cathode in the novel battery within good performance. The novel battery presented better cycling stability than K–SPAN battery. We obtained a highly reversible capacity of 513 mAh g−1 and excellent cycling performance of 490 mAh g−1 retention after 100 cycles at a current density of 35 mA g−1, in addition the coulombic efficiency approximately approached to 100% in successive cycles. [ABSTRACT FROM AUTHOR]

• The triple failure pressure evaluation system for corroded pipelines is proposed. • FE models are developed for predicting triple failure pressure of corroded pipes. • The influence of external loads on failure pressure of corroded pipes is clarified. • A BPNN model is established to efficiently predict the triple failure pressure. • The multiple failure assessment diagram method for corroded pipelines is proposed. With the complexity of geological conditions and corrosive environments, the evaluation of failure pressure for defective pipelines under external loads has gradually become an important part of pipeline integrity management and reliability assessment. In this study, validated, 3D, nonlinear finite element (FE) models are established. Considering the safety margin in the evaluation process of corroded pipelines, the evaluation system of triple failure pressure is proposed. Subsequently, many simulations have been carried out with validated FE models. The obtained dataset is selected for training the backpropagation neural network (BPNN) model. After hyperparameter analysis and comparison, the triple failure pressure prediction BPNN model, which is based on a 9-dimensional input layer, a 7-dimensional 180-node hidden layer and a 3-dimensional output layer, is established. Through double verification, it is considered that the established BPNN model has high accuracy in predicting the ultimate burst pressure of corroded pipelines. While rapidly predicting the ultimate burst pressure, the model can synchronously output the flow failure pressure and yield failure pressure. With the established deep learning model, the multiple failure assessment curves of defective pipelines are automatically generated within seconds, which provides a convenient evaluation reference for the defect problems encountered in practical engineering. [ABSTRACT FROM AUTHOR]

Abstract: In contrast to a conventional symmetric Lorentzian resonance, Fano resonance is predominantly used to describe asymmetric-shaped resonances, which arise from the constructive and destructive interference of discrete resonance states with broadband continuum states. This phenomenon and the underlying mechanisms, being common and ubiquitous in many realms of physical sciences, can be found in a wide variety of nanophotonic structures and quantum systems, such as quantum dots, photonic crystals, plasmonics, and metamaterials. The asymmetric and steep dispersion of the Fano resonance profile promises applications for a wide range of photonic devices, such as optical filters, switches, sensors, broadband reflectors, lasers, detectors, slow-light and non-linear devices, etc. With advances in nanotechnology, impressive progress has been made in the emerging field of nanophotonic structures. One of the most attractive nanophotonic structures for integrated photonics is the two-dimensional photonic crystal slab (2D PCS), which can be integrated into a wide range of photonic devices. The objective of this manuscript is to provide an in depth review of the progress made in the general area of Fano resonance photonics, focusing on the photonic devices based on 2D PCS structures. General discussions are provided on the origins and characteristics of Fano resonances in 2D PCSs. A nanomembrane transfer printing fabrication technique is also reviewed, which is critical for the heterogeneous integrated Fano resonance photonics. The majority of the remaining sections review progress made on various photonic devices and structures, such as high quality factor filters, membrane reflectors, membrane lasers, detectors and sensors, as well as structures and phenomena related to Fano resonance slow light effect, nonlinearity, and optical forces in coupled PCSs. It is expected that further advances in the field will lead to more significant advances towards 3D integrated photonics, flat optics, and flexible optoelectronics, with lasting impact in areas ranging from computing, communications, to sensing and imaging systems. [Copyright &y& Elsevier]

• The dynamic process of SRB corrosion product film formation was revealed. • Without a culture medium, the biofilm formed was relatively thin, but the adhesion and corrosiveness were stronger. • The structural characteristics of corrosion biofilm in the solution with different nutrient concentrations were clarified. In this work, the effects of different nutrient contents in simulated soil solution containing sulfate-reducing bacteria (SRB) on the corrosion of X80 pipeline steel were studied. The highest amount of sessile SRB was found in the initial medium concentration of 1/3, followed by the concentration of 10%, and the lowest in the simulated soil solution without culture medium. However, the biofilm formed in the simulated soil solution without culture medium had the strongest adhesion and corrosiveness, with X80 steel having the highest corrosion rate, which was approximately 7.2 times of the initial medium concentration of 1/3. The research results have a positive role in promoting the development of SRB corrosion prevention technology for buried pipeline. [ABSTRACT FROM AUTHOR]

Sulfurized polyacrylonitrile (SPAN) cathode shows excellent electrochemical performance in carbonate electrolyte for lithium-sulfur batteries. However, the limited redox conversion rate of SPAN cathode in ether electrolyte would lead to high solubility of the intermediate polysulfide Li 2 S n (n ≤ 4) and shuttling, resulting in a low performance of corresponding lithium-sulfur battery, even though ether-based electrolytes are more suitable in terms of Li metal anode. In addition, SPAN is comparatively lower sulfur loading (<50 wt%) reduced its value. Improving the sulfur loading and accelerate the redox conversion of SPAN to be compatible with ether electrolyte will be one of the most promising cathode of lithium-sulfur batteries. Here, we introduced a sulfurized polyacrylonitrile cathode (SPAN-DG) with high sulfur loading (52 wt%) and high conductivity prepared by diphenylguanidine as vulcanization accelerator into lithium-sulfur battery based on ether electrolyte. This study found that SPAN-DG cathode with high conductivity can fast reaction kinetics and successfully inhibit the dissolution of lithium polysulfide and shuttle in ether electrolytes, shows good electrochemical performance. SPAN-DG cathode deliver a specific capacity of 879 mAh g−1 and 661 mAh g−1 (based on the mass of cathode) at rates of 0.1C and 1C (1C = 700 mA g−1), respectively. • SPAN-DG cathode shows high sulfur loading and high conductivity. • SPAN-DG cathode can inhibit dissolution of lithium polysulfide in ether electrolyte. • SPAN-DG deliver 895 mAh g−1 discharge capacity in ether electrolyte for Li–S battery. [ABSTRACT FROM AUTHOR]

This work provides a new systematic evaluation method to assess the interaction between adjacent corrosion defects and its effect on the integrity of pipelines. First, a finite element (FE) model of a pipeline containing adjacent defects (defects in longitudinal, circumferential and diagonal alignments) was developed. Then, the detailed relationships between defect spacing, and geometry, as well as the burst pressure of the pipe were investigated. At last, an interaction identification criterion applicable to asymmetrical defects was proposed, whose accuracy and reliability of the criterion were validated by FE simulations. The results show that the arrangement of corrosion affects the effect of interaction between adjacent defects. Regarding defects in longitudinal and circumferential alignments and with different depths, the increase of defect spacing strengthens the interaction between defects. For diagonally and circumferentially aligned defects with an identical depth, interaction strength tends to decrease first and then increase with the rise of defect spacing. An increase in defect depth exacerbates the interaction between adjacent corrosions. Similarly, an increase in the length of the shorter defect enhances the interplay between defects, which thus reduces the burst capacity of the pipe. When the length of the longer defect in adjacent defects increases, the interaction between the defects will be weakened, and the burst pressure of the pipeline is mainly dominated by the longer defect. Diagonally aligned defects show the strongest interaction effect when their overlapped distance in axial projection equals the sum of depths of adjacent defects, followed by defects in a longitudinal alignment. Besides, defects in a circumferential alignment have little effect on the failure pressure of the pipe. It is expected that the proposed interaction assessment criterion for adjacent defects with different arrangement types can provide a reference for assessing the integrity of pipelines with cluster corrosion defects. • A novel interaction assessment method applicable to asymmetrical defects and diagonally aligned defects was proposed. • The relationships between defect spacing, defect geometry and the burst capacity of corroded pipelines were clarified. • The arrangement with the most significant interaction for various alignments of defects was determined. • The developed interaction criterion shows a high accuracy in identifying the interacting defects. [ABSTRACT FROM AUTHOR]

Magnetic anomaly detection is becoming increasingly prevalent for detecting and locating the buried pipelines. The detection performance is often hindered by adjacent pipeline, near-field ferromagnetic objects and random noises. In order to overcome these obstacles, a magnetic anomaly detection method based on deep learning neural networks (DLNN) is proposed to decouple and denoise the integrated detection to accurately extract the magnetic anomaly of single pipeline. The theoretical derivation of the vertical component of magnetic anomaly was executed based on Poisson's equation. Then the integrated detection was simulated by summing magnetic anomalies of parallel pipelines and metal sphere, as well as white Gaussian noise. The DLNN was constructed with improved optimization design, and trained using supervised learning method. The results show that the proposed method exhibits almost immune to random noises, the prediction accuracy approaches to 90% with signal to noise ratio (SNR) of 30 dB. Meanwhile, the predictive accuracy is still above 80% with interferences both from near-field ferromagnetic objects and random noises with SNR of 30 dB. The method becomes practically significant in the development of geomagnetic inspection instruments for the adjacent parallel pipelines. • The expressions of magnetic anomaly are derived based on Poisson's equation. • A deep learning neural networks is constructed with improved design. • Extracting magnetic anomaly of single pipeline accurately. • Prediction accuracy approaches to 90% with signal to noise ratio drops to 30 dB. [ABSTRACT FROM AUTHOR]

The soil response to large earthquakes is strongly nonlinear, which has a significant influence on the performance of buried infrastructure as well as input motion to superstructures. This paper reports on uniform and non-uniform multi-point shaking table tests to elucidate the effect of soil non-linearity on free-field soil response. Emphasis was placed on investigating the effect of the non-uniform seismic excitation in different directions on the soil response. The tests were conducted on scaled sand deposits enclosed in a suspension continuum soil box using three shaking tables that can induce uniform and non-uniform seismic excitations. Quantitative analyses were performed to study the ground motion response characteristics and variation of free-field soil characteristics underground motions with different intensity, frequency content and directions. The analyses evaluated the soil dynamic characteristics and their variation with strain level, as well as soil acceleration and settlement responses. The results demonstrated that the soil nonlinear behavior is influenced by the ground motion intensity, direction (longitudinal or transverse) and uniformity. Non-uniform ground motion may lead to more pronounced changes of soil structure, which would decrease the soil profile natural frequency and increase its damping ratio. The variation of soil shear modulus with strain also reflected the soil plastic response. The longitudinal excitation had a more pronounced effect on the soil vertical settlement compared with the transverse excitation. However, non-uniform excitation had a minor effect on the soil vertical settlement. • A shaking table test for scaled sand under multi-point non-uniform seismic excitation is performed. • The soil nonlinear behavior is influenced by not only the ground motion intensity but also its direction. • The frequency band of the acceleration spectra was wider, the number of peaks was larger under non-uniform excitations. • The variation of soil shear modulus with strain also reflected the soil plastic response. • The transverse excitation had a minor effect on the soil vertical settlement compared with the longitudinal excitation. [ABSTRACT FROM AUTHOR]