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This document is a guest editorial for a virtual special issue titled "Structural Integrity in the Context of Carbon Neutrality." The issue focuses on the importance of structural integrity in achieving carbon neutrality and features twelve papers that highlight breakthroughs in structural integrity research related to carbon neutrality. The papers cover topics such as suppressing hydrogen embrittlement, improving the reliability of conventional energy conversion systems, understanding fatigue failure mechanisms in gas turbine engines, investigating material properties and damage mechanisms, studying crack growth behavior, and enhancing the fatigue life of welded joints. The authors express their gratitude to the session chairs, reviewers, and authors for their contributions to the special issue. [Extracted from the article]

Damages caused by the effects of cyclic loading (fatigue) and high temperature (creep and oxidation) have been considered critical and need to be appropriately evaluated. A series of strain‐controlled fatigue and creep‐fatigue tests are performed on P92 at 873 K under oxygen‐containing environment. The creep‐fatigue life prediction results are summarized using models based on strain‐range partition, Manson–Coffin equation and linear damage summation (LDS) rule. Obviously, the models based on the LDS rule show relatively good performance with an error band of ±2.5. In view of the adverse effects of oxidation on creep‐fatigue endurance, this paper further develops a physically‐based oxidation damage equation, which is incorporated into LDS rule for the improvement of life assessment. The predicted and experimental results falling into ±1.5 error band proved the accuracy of the proposed oxidation damage equation in the LDS rule. Additionally, model selection criteria are recommended to evaluate the model prediction capabilities. Highlights: A series of fatigue, creep‐fatigue, and oxidation tests are performed on P92 at 873 K.Oxidation damage equation based on kinetics and concentration distribution is proposed.Error band is reduced from ±2.5 to ±1.5 by using the proposed oxidation damage equation.W‐SEDE‐O model performs best with the minimum error band & best statistical indicators. [ABSTRACT FROM AUTHOR]

Ductile crack growth behaviours of TP304 pipes containing different circumferential defects were investigated in the study. Finite element (FE) damage analysis of the ductile fracture was carried out based on an uncoupled multiaxial fracture strain energy (MFSE) model with only two model parameters, which can be calibrated by data from tensile tests and fracture toughness tests. For the purpose of comparison, the Gurson–Tvergaard–Needleman (GTN) model was also employed in the FE damage analysis. It is observed that the MFSE model can reproduce the ductile tearing experiments as excellently as the GTN model does. Despite its simplicity, the MFSE model can reasonably predict the magnitudes of the crack initiation load and maximum load, the load‐line displacement, the crack mouth opening displacement, the crack extension and the crack profiles in the full‐scale cracked pipe tests. [ABSTRACT FROM AUTHOR]

Background: Long noncoding RNAs (lncRNA) are important in the growth and metastasis of colon cancer. The objective of this study was to describe the potential role of lncRNA NEAT1 in the progression of colon cancer. Methods: Quantitative real‐time polymerase chain reaction was used for detecting NEAT1, miR‐185‐5p, and IGF2 in colon cancer cells and tissues. The potential diagnostic value of NEAT1 in colon cancer was analyzed with the receiver operating characteristic curve. Kaplan–Meier method was applied for evaluating the association between NEAT1 expression and the overall survival of osteosarcoma patients, whereas Transwell assay was introduced to examine the potential invasion and migration of colon cancer cells. In addition, the binding of NEAT1/IGF2 to miR‐185‐5p was confirmed by RNA pull‐down and RNA‐binding protein immunoprecipitation assays and dual‐luciferase reporter gene assay. Finally, rescue experiments were conducted to confirm the role of NEAT1/miR‐185‐5p/IGF2 axis in colon cancer. Results: Colon cancer patients with low NEAT1 expression presented with longer overall survival than those with high expression. The migration and invasion of colon cancer cells were considerably promoted by overexpressed NEAT1. Both NEAT1 and IGF2 bound to miR‐185‐5p. Conclusion: NEAT1 upregulate IGF2 expression through absorbing miR‐185‐5p to enhances the migration and invasion of colon cancer cells. [ABSTRACT FROM AUTHOR]

The stress state is one of the most notable factors that dominates the initiation of ductile fracture. To examine the effects of the stress state on plasticity and ductile failure, a new tension‐shear specimen that can cover a wide range of stress triaxialities was designed. A fracture locus was constructed in the space of ductility and stress triaxiality for two typical steels based on a series of tests. It is observed that the equivalent plastic strain at failure exhibits a nonmonotonic variation with increasing the value of stress triaxiality. A simple damage model based on the ductility exhaustion concept was used to simulate the failure behaviour, and a good agreement is achieved between simulation results and experimental data. It is further shown that consideration of fracture locus covering a wide range of stress triaxialities is a key to an accurate prediction. Highlights: A tension‐shear specimen covering a wide range of stress triaxialities is newly designed.The obtained fracture locus is a nonmonotonic function of the stress triaxiality.A simple strain‐based damage model incorporating the obtained fracture locus can well predict the ductile fracture behaviour.Consideration of fracture locus covering a wide range of stress triaxialities is a key to accurate prediction. [ABSTRACT FROM AUTHOR]

High-temperature components in power plants may fail due to creep and fatigue. Creep damage is usually accompanied by the nucleation, growth, and coalescence of grain boundary cavities, while fatigue damage is caused by excessive accumulated plastic deformation due to the local stress concentration. This paper proposes a multiscale numerical framework combining the crystal plastic frame with the meso-damage mechanisms. Not only can it better describe the deformation mechanism dominated by creep from a microscopic viewpoint, but also reflects the local damage of materials caused by irreversible microstructure changes in the process of creep-fatigue deformation to some extent. In this paper, the creep-fatigue crack initiation analysis of a modified 12%Cr steel (X12CrMoWvNBN10-1-1) is carried out for a given notch specimen. It is found that creep cracks usually initiate at the triple grain boundary junctions or at the grain boundaries approximately perpendicular to the loading direction, while fatigue cracks always initiate from the notch surface where stress is concentrated. In addition to this, the crack initiation life can be quantitatively described, which is affected by the average grain size, initial notch size, stress range and holding time. [ABSTRACT FROM AUTHOR]

Planar solid oxide fuel cell (SOFC) operates at high temperature and requires a good creep strength to ensure the structure integrity. This paper presents a creep and damage analysis of a bonded compliant seal (BCS) structure of a planar SOFC considering the effect of as-bonded residual stress and thermal stress, as well as the effect of filler metal and foil thickness. A modified continuum creep-damage model is used in the finite element simulation. It demonstrates that the BCS structure meets the requirement of the long-term operation at the high temperature of 600 °C with an appropriate braze bonding process. The results show that the failure location is not in the region of maximum creep deformation due to the effect of high level multi-axial stress which drastically decreases the multi-axial ductility. Reasonably reducing the thickness of filler metal and foil can decrease the damage of the BCS structure. Based on the consideration of creep and damage, it is proposed that the thickness of filler metal and foil should not exceed 0.1 and 0.05 mm, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Bonded compliant seal is a new sealing design for planar solid oxide fuel cell. During brazing, large residual stresses are generated which have a great effect on failure of the brazing connection. Therefore, how to decrease the residual stresses is a critical issue for structure integrity. This paper presents a study on decreasing residual stresses by using short-time creep relaxation effect. A sequential-coupled calculation model is developed based on finite element method. The brazing temperature field is firstly obtained by simulating the convection and radiation heating, and then the residual stress is calculated by a thermal-elasto-plastic-creep model. The calculated results are verified by neutron diffraction measurements. During cooling, a short holding time at 600 °C is designed to relax the residual stress by creep effect. The results show that this effect has a remarkable impact on decreasing the residual stress. The stresses in cell, Ag–CuO and foil have been reduced by about 26.9%, 13.6% and 22.1%, respectively, as the holding time increases up to 40 h. When the holding time exceeds 40 h, the residual stresses remain almost unchanged. It is thus suggested that the holding time should be reasonably determined to allow sufficient stress relaxation. [Copyright &y& Elsevier]

Two chiral tetraphenylenes, 2,15-dideuteriotetraphenylene (7) and 2,7-dimethyltetraphenylene (15) were synthesized and resolved to address the tetraphenylene inversion barrier problem. Neutron diffraction investigation of enantiopure 7 showed that the molecule retained its chirality integrity during its synthesis from enantiopure precursors and therefore rules out the possibility of the tetraphenylene framework possessing a low-energy barrier to inversion. Thermal study on 15 and tetraphenylene 1 further revealed that their inversion barriers were not overcome up to 600 degrees C, at which temperature these compounds underwent skeletal contraction into triphenylene with activation energies of 62.8 and 58.2 kcal/mol, respectively. This result is supported by computational studies which yielded an inversion barrier of 135 kcal/mol for tetraphenylene as a consequence of the peri-hydrogen repulsions at its planar conformation.

This paper concerns the synthesis of 1,16-dihydroxytetraphenylene (DHTP) (2) by employing a novel NBS bromination route. (+/-)-DHTP 2 was successfully resolved into its optical antipodes and converted to (+/-)-1,16-bis(diphenylphosphino)tetraphenylene (BPTP) (26), whose platinum complex BPTP-PtCl(2) (27) was also obtained. As a hydrogen bond donor, racemic and optically active DHTP 2 was allowed to assemble with 4,4'-bipyridine to form single crystals of good quality. X-ray Diffraction studies of these crystals revealed that the crystallographic packing of the hydrogen bonded complex between (+/-)-2 and 4,4'-bipyridine was different from the one formed from (S)-2 and 4,4'-bipyridine. It was found that an infinite zigzag chain with alternate chirality was formed in the assembly of (+/-)-2 and 4,4'-bipyridine, while (S)-2 and 4,4'-bipyridine failed to show the same assembly pattern. The reason (+/-)-2 formed an alternate and zigzag chain with 4,4'-bipyridine was most likely due to the inherent stability of this supramolecular assembly. The chiral recognition between 2 and optically active BINAP under the direction of platinum(II) has also been examined. (1)H and (31)P NMR spectroscopic studies demonstrated that there was an obvious discrimination of 2 between the enantiomers of BINAP-PtCO(3).