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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]

Background: Augmentation of oxidative stress after estrogen deficiency leading to functional deficiency of jawbone bone marrow mesenchymal stem cells (BMSCs) causes jawbone loss in osteoporosis. OSGIN2, an oxidative stress induced factor, has been found to be associated with skeletal diseases. This study aims to investigate the function of OSGIN2 in jawbone BMSCs of osteoporotic rats. Jawbone BMSCs were used. Results: Oxidative stress was increased in jawbone BMSCs of osteoporotic rats, meanwhile OSGIN2 was also up-regulated. Osteogenesis of jawbone BMSCs was declined under oxidative stress, while silence of OSGIN2 ameliorated the osteogenic deficiency. RORα and its downstream osteogenic markers (BSP and OCN) decreased under oxidative stress, while knocking-down of OSGIN2 restored their expressions. Inhibition of OSGIN2 improved the osteogenesis of jawbone BMSCs under oxidative stress, whereas down-regulation of RORα offset the effect. Intra-jawbone infusion of si-OSGIN2 rescued jawbone loss and promoted new bone deposition of osteoporotic rats. Conclusions: Oxidative stress is redundant in osteoporosis, which results in up-regulation of OSGIN2. OSGIN2 restricts osteogenic ability of jawbone BMSCs via regulating RORα, while silencing of OSGIN2 rescues the osteogenic deficiency of osteoporotic rats. [ABSTRACT FROM AUTHOR]

Objective: To generalize the oral manifestations related to malaria and discuss their clinical significance for health professionals. Materials and Methods: The bibliographic databases of Public MEDLINE, Embase, Web of Science and Scopus were employed to retrieve publications online from January 1781 to August 2019. Original research articles, clinical trials, and case reports published in English were included. Results: A small number of studies reported oral manifestations of malaria (n = 29), including gingival bleeding, glossitis, oral ulcer, abnormal oral pigmentation, pericoronitis, herpes labialis, herpes gingivostomatitis, bitter taste, sore throat, Burkitt lymphoma of the jaw, alveolar bone resorption, and enamel hypoplasia. Conclusion: Oral manifestations may be important indicators for identification of malaria. Dental and general professionals should pay more attention to oral manifestations in malaria cases, and guide them for specialized examination, diagnosis, and management. [ABSTRACT FROM AUTHOR]

Malaria is a worldwide parasitic disease, which affects millions of lives every year. Various medications are recommended by WHO for prevention and treatment of malaria. However, adverse events caused by antimalarials were frequently reported, some of which were severe and fatal. Disorders of many organs related to antimalarials have been well recognized, whereas few studies concentrated on the relationship between antimalarials and oral‐maxillofacial system health. Current review generalized the relevance of antimalarials to the health of oral‐maxillofacial part and raised an urgent need to form a standard management for antimalarial‐related oral‐maxillofacial adverse events. [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]

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]

• 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]

Bars: 25 m. (e,f) The corresponding parameter of TRAP and the serum bone resorption marker detected by enzyme-linked immunosorbent assay (ELISA) showed that miR-21 deficiency blocked age-related osteoclastogenesis and bone resorption. (d) Enzyme-linked immunosorbent assay (ELISA) detection of the serum bone resorption marker of 3-month WT and miR-21-/- mice. miR-21 deficiency inhibited the bone resorption rate. [Extracted from the article]

Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system, such as Mars, the moon, and asteroids. To date, the origin mechanisms of perchlorate and chlorate on the Martian surface have been well-established; however, relatively little attention has been cast to airless bodies. Here, we experimentally investigated the potential oxidation mechanisms of chloride to chlorate and perchlorate, such as ultraviolet irradiation under H2O- and O2-free conditions and mechanical pulverization processes. Individual minerals, olivine, pyroxene, ilmenite, magnetite, TiO2 and anhydrous ferric sulfate, and lunar regolith simulants (low Ti, CLRS-1; high-Ti, CLRS-2) and their metallic iron (Fe0) bearing counterparts were examined. We found that pulverization of dry matrix material-halite mixtures, even in the presence of O2, does not necessarily lead to perchlorate and chlorate formation without involving water. Under photocatalytic and H2O- and O2-free conditions, olivine and pyroxene can produce oxychlorine (ClOx−) species, although the yields were orders of magnitude lower than those under Martian-relevant conditions. Nanophase-Fe0 particles in the lunar regolith and the common photocatalyst TiO2 can facilitate the ClOx− formation, but their yields were lower than those with olivine. The oxides ilmenite and magnetite did not efficiently contribute to ClOx− production. Our results highlight the critical role of H2O in the oxidation chloride to chlorate and perchlorate, and provide essential insights into the environmental influence on the formation of oxychlorine species on different celestial bodies. [ABSTRACT FROM AUTHOR]

Environment and energy are two key issues in today’s society. In terms of environmental protection, the treatment of phytoremediation residues has become a key problem to be solved urgently, while for energy storage, it tends to utilize low-cost and high specific energy storage materials (i.e. porous carbon). In this study, the phytoremediation residues is applied to the storage materials with low-cost and high specific capacity. Firstly, the phosphorous acid assisted pyrolysis of oilseed rape stems from phytoremediation is effective in the removal of Zn, Cu, Cd and Cr from the derived biochar. Moreover, the derived biochar from phytoremediation residues shows abundant porous structure and polar groups (â€"O/â€"P/â€"N), and it can deliver 650 mAh gâˆ'1 with 3.0 mg cmâˆ'2sulfur, and keeps 80% capacity after 200 cycles when employing it as a sulfur host for lithiumâ€"sulfur (Liâ€"S) batteries. Hence, phosphorous acid assisted pyrolysis and application in Liâ€"S battery is a promising approach for the disposal of phytoremediation residues, which is contributed to the environmental protection as well as energy storage. [ABSTRACT FROM AUTHOR]

Background: Oral squamous cell carcinoma (OSCC), as one of the commonest malignancies showing poor prognosis, has been increasingly suggested to be modulated by circular RNAs (circRNAs). Through GEO (Gene Expression Omnibus) database, a circRNA derived from ZDBF2 (circZDBF2) was uncovered to be with high expression in OSCC tissues, while how it may function in OSCC remains unclear.Methods: CircZDBF2 expression was firstly verified in OSCC cells via qRT-PCR. CCK-8, along with colony formation, wound healing, transwell and western blot assays was performed to assess the malignant cell behaviors in OSCC cells. Further, RNA pull down assay, RIP assay, as well as luciferase reporter assay was performed to testify the interaction between circZDBF2 and RNAs.Results: CircZDBF2 expressed at a high level in OSCC cells and it accelerated OSCC cell proliferation, migration, invasion as well as EMT (epithelial-mesenchymal transition) process. Further, circZDBF2 sponged miR-362-5p and miR-500b-5p in OSCC cells to release their target ring finger protein 145 (RNF145). RNF145 expressed at a high level in OSCC cells and circZDBF2 facilitated RNF145 transcription by recruiting the transcription factor CCAAT enhancer binding protein beta (CEBPB). Moreover, RNF145 activated NFκB (nuclear factor kappa B) signaling pathway and regulated IL-8 (C-X-C motif chemokine ligand 8) transcription.Conclusion: CircZDBF2 up-regulated RNF145 expression by sponging miR-362-5p and miR-500b-5p and recruiting CEBPB, thereby promoting OSCC progression via NFκB signaling pathway. The findings recommend circZDBF2 as a probable therapeutic target for OSCC. [ABSTRACT FROM AUTHOR]

The failure of one pipeline may compromise the integrity of adjacent pipelines, especially for closely spaced parallel pipelines. This paper presents a series of multipoint shaking table tests of parallel double pipelines, which were installed in sand beds with three different spacing values to assess the effect of spacing on the seismic response of parallel pipelines. The acceleration and strain data were collected during the shaking tests. The results demonstrated that the acceleration response of soil between the two pipelines under uniform and nonuniform excitation was relatively lower than that of the pipelines due to the influence of the adjacent double pipelines, especially for the nonuniform excitation case. The maximum peak strain values of both pipelines gradually increased as the spacing between them increased under uniform excitation at lower loading intensity. However, for nonuniform excitations and uniform excitation of higher loading intensity, the maximum peak strain of pipelines with spacing of 150 mm was smaller than that with spacing of 100 and 200 mm. These results indicate that the combination of different pipeline spacings and nonuniform excitation could make the pipeline dynamic response more complicated, which should be properly considered in the seismic design of parallel double pipelines. [ABSTRACT FROM AUTHOR]

• 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]