Stress Release Research Articles

Unloading damage evolution and rockburst risk assessment of Xuefengshan No.1 tunnel by combining multiple approaches

Large-scale rock burst disasters often occur in high-stress and deep-buried tunnels, due to challenges in accurate forecasting and the lack of clarity regarding the underlying mechanisms largely. This study combined on-site stress drilling tests, coupled finite and discrete element simulations, and theoretical calculations to examine unloading damage, rockburst evolution, and deformation failure of the high-stress and deep-buried Xuefengshan No.1 tunnel. The initial geo-stress characteristics were inversed to explore the unloading damage evolution and failure mechanism. The influences of stress distribution, displacement development, and energy release on the stability and rock burst risk of surrounding rock masses were analyzed. The rock burst risks along this tunnel were assessed by the energy method and stress intensity ratio method comprehensively. The findings revealed that displacement convergence and stress release caused by unloading during tunnel excavation were most prominent at the tunnel invert and the arch waist on both sides. The displacement of the rock mass within the unloading zone exhibited a symmetrical distribution along the tunnel axis, with displacement gradually decreasing radially outward. The deep-buried granite and slate sustained greater damage during the rockburst compared to sandstone. There were approximately 6500 m of the Xuefengshan No.1 tunnel, accounting for 55.7% of its total length, possessing potential rock bursts, predominantly at weak to moderate levels. The likelihood of rock bursts increased with burial depth, with a marked rise in risk when the depth exceeded 300 m. The results of this study could provide valuable insights into the geo-stress characteristics and rockburst risk assessment for high-stress and deep-buried tunnels.

Functionally Graded Oxide Scale on (Hf,Zr,Ti)B2 Coating with Exceptional Ablation Resistance Induced by Unique Ti Dissolving.

Multicomponent Ti-containing ultra-high temperature ceramics (UHTCs) have emerged as more promising ablation-resistant materials than typical UHTCs for applications above 2000 °C. However, the underlying mechanism of Ti improving the ablation performance is still obscure. Here, (Hf,Zr,Ti)B2 coatings are fabricated by supersonic atmospheric plasma spraying, and the effects of Ti content on the ablation performance under an oxyacetylene flame are investigated. The (Hf0.45Zr0.45Ti0.10)B2 coating shows superior ablation resistance and cycling reliability at ≈2200°C. A functionally graded oxide scale comprising an outer dense layer and an underlying fine granular layer formed. The former is a better oxygen barrier owing to fewer cracks and the latter has high strain tolerance due to finer grain size. The uniform dissolving of ≈4 mol% Ti in the inner layer results in grain refinement via sluggish diffusion and thus stress release. For the outer layer, Ti segregation at the nanoscale leads to a metastable cubic (Hf,Zr,Ti)O2 and local severe lattice distortion, inhibiting the propagation of cracks. Ti ions' unique dissolving in the oxide scale enables a strong oxygen diffusion barrier with high strain tolerance, which is responsible for superior performance. This study provides new insights into the ablation behavior of Ti-containing multicomponent UHTCs.

Stress Release of Zincophilic N-Doped Carbon@Sn Composite on High-Curvature Surface of Zinc Foam for Dendrite-Free 3D Zinc Anode.

Commercial 3D zinc foam anodes with high deposition space and ion permeation have shown great potential in aqueous ion batteries. However, the local accumulated stress from its high-curvature surface exacerbates the Zn dendrite issue, leading to poor reversibility. Herein, we have employed zincophilic N-doped carbon@Sn composites (N-C@Sn) as nano-fillings to effectively release the local stress of high curvature surface of 3D Zn foams toward dendrite-free anode in aqueous zinc ion battery (AZIB). These electronegative and conductive N-C@Sn nano-fillings as supporters can provide a highly zincophilic channel for initial Zn nucleation and reduce local current density for regulating Zn deposition. Uniform Zn deposition further assists homogenous stress distribution on the platting surface, which gives a positive feedback loop to improve anode reversibility. As a result, zinc foam with N-C@Sn composite (ZCSn Foam) symmetric cell achieves a long cycle lifespan of 1100h at 0.5mA cm-2, much more than that of Zn Foam (∼80h lifespan). The full cell ZCSn Foam||MnO2 exhibits remarkable reversibility with 67% retention after 1000 cycles at 0.8 A g-1 and 76% after 1600 cycles at 2 Ag-1. This 3D-constructing strategy may offer a promising and practical pathway for metal anode application.

Light-Driven Adaptive Molecular Crystals Activated by [2+2] and [4+4] Cycloadditions.

Photomechanical crystals act as light-driven material-machines that can convert the energy carried by photons into kinetic energy via shape deformation or displacement, and this capability holds a paramount significance for the development of photoactuated devices. This transformation is usually attributed to anisotropic expansion or contraction of the unit cell engendered by light-induced structural modifications that lead to accumulation and release of stress that generates a momentum, resulting in readily observable mechanical effects. Among the available photochemical processes, the photoinduced [2+2] and [4+4] reactions are known for their robustness, predictability, amenability to control with molecular and supramolecular engineering approaches, and efficiency that has already been elevated to a proof-of-concept smart devices based on organic crystals. This review article presents a summary of the recent research progress on photomechanical properties of organic and metal-organic crystals where the mechanical effects are based on [2+2] and [4+4] cycloaddition reactions. It consolidates the current understating of the chemical strategies and structure-property correlations, and highlights the advantages and drawbacks of this class of adaptive crystals within the broader field of crystal adaptronics.

Suppression of Sepsis Cytokine Storm by Escherichia Coli Cell Wall-Derived Carbon Dots.

Sepsis is a life-threatening disease caused by a dysregulated immune response to infection, often involving the translocation of Gram-negative bacteria such as Escherichia coli (E. coli) into the bloodstream, triggering a cytokine storm. Despite its severity, no effective drugs currently exist for sepsis treatment. This study explores whether pathogen-derived carbon dots can mitigate their inherent toxicity while leveraging their structural similarity to pathogens to competitively bind pattern recognition receptors, thereby inhibiting sepsis. Based on this concept, E. coli wall-derived carbon dots (E-CDs) are synthesized and shown to reduce inflammatory cytokine production, protect organ function, and improve survival in septic mice. Mechanistic studies reveal that E-CDs competitively bind to lipopolysaccharide-binding protein with lipopolysaccharide, promoting toll-like receptor 4 degradation via the lysosomal pathway and inhibiting nuclear factor kappa-B (NF-κB) activation. Additionally, E-CDs exhibit antioxidant properties, reducing oxidative stress and mitochondrial DNA release, thereby suppressing overactivation of the stimulator of interferon genes pathway. In septic cynomolgus monkeys and patient-derived peripheral blood mononuclear cells, E-CDs alleviate inflammation and oxidative stress. Overall, this study demonstrates that E-CDs can suppress the cytokine storm in sepsis by co-silencing innate immune pathways, suggesting that converting pathogens into carbon dots offers a novel therapeutic strategy.

Suitable thickness of the adhesive layer facilitates the release of thermal stress in AlN crystals

In this work, the relation between the thickness of the adhesive layer and the thermal stress was investigated and the optimal adhesive thickness was determined by a combination of theoretical and experimental methods.

Investigating the impact of omega-3 fatty acids on oxidative stress and pro-inflammatory cytokine release in iPSC-derived forebrain cortical neurons from ADHD patients

Investigating the impact of omega-3 fatty acids on oxidative stress and pro-inflammatory cytokine release in iPSC-derived forebrain cortical neurons from ADHD patients

The influence of mechanical constraints on Li diffusion and stress in bilayer electrode of lithium-ion batteries

Lithium-ion batteries (LIBs) are widely used in portable electronic devices, electric vehicles, and other fields. With the rapid development of its application fields, there is an urgent need to further improve its energy density and safety. During the charging/discharging process of the LIBs, the diffusion of Li will cause local volumetric change in the electrode material. The degradation and damage of the electrode material structure caused by diffusion-induced deformation is a major obstacle to the development of LIBs. Generally speaking, the electrode materials in LIBs are always subject to specific external constraints, including both inevitable passive structural constraints within the battery and external active constraints that may be imposed by emerging technology application scenarios, which can also affect the mechanical properties of the electrode materials. Therefore, a deeper understanding of the diffusion-induced stress and Li concentration changes in the electrode material is an engineering requirement for developing new material design paradigms to enhance the overall performance of LIBs. In this work, a two-way diffusion-stress coupling model is used to discuss the effect of the four different levels of idealized deformation constraints on the Li concentration and stress in the bilayer plate electrode during the charging process through the numerical solution. From a mechanical perspective, the bilayer plate electrode structure has two degrees of freedom: lateral expansion and bending deformation. Weakened constraint conditions can partially or completely activate these stress release mechanisms, thereby reducing the overall stress level of the electrode structure and improving its mechanical stability. However, from an electrochemical perspective, the stress gradient generated by the forward bending deformation of the electrode structure can hinder the Li intercalation process. Enhanced constraints can partially or completely suppress the forward bending of the electrode, making the Li concentration in the active layer more uniform and thus improving the capacity utilization efficiency of the active layer. These results not only provide theoretical references for further understanding the chemical-mechanical response of the bilayer electrodes under more realistic or extreme service conditions, but also indicate from a design perspective that compromised external constraints are beneficial for balancing the structural durability and electrochemical performance of electrodes.

Wrinkled thermoplastic polyamide elastomer foams with enhanced mechanical properties fabricated by dynamic supercritical CO2 foaming

AbstractWrinkled foams (WF), distinguished by their numerous cell wall wrinkles, exhibit superior impact resistance compared to conventional foams (CF), making them ideal for applications such as sports protection and packaging. Despite their potential, the mechanisms behind wrinkle formation remain underexplored, limiting production and process optimization. In this study, we use a custom supercritical foaming reactor with a sapphire glass viewing window to investigate the differences between wrinkled and conventional thermoplastic polyamide elastomer foams. Our findings suggest that “excessive expansion‐shrinkage” is crucial for wrinkle development. Molecular dynamics simulations reveal that molecular chains align with the flow field of dynamic CO2, which increases the intramolecular stress. The release of intramolecular stress triggers wrinkle formation, driven by thermodynamic instability. Furthermore, comparisons of the impact resistance and compression performance between WF and CF show that wrinkled structures alter the deformation behavior under force. The wrinkles facilitate increased collision, squeezing, and friction between cell walls, thus dissipating energy as heat and creating “micro‐air units” that enhance cushioning capability. These distinctive characteristics make WF a promising material for high‐performance applications in cushioning and energy absorption, such as in sports protection and packaging.Highlights Wrinkled polyamide foams are fabricated by dynamic scCO2 foaming. Chain stretching and shrinkage under scCO2 flow are verified by MD simulation. Excessive expansion‐shrinkage foaming behavior causes the wrinkled structure. Wrinkled structure greatly increases the impact absorption ability.

A case study of integrative psychospiritual techniques in addressing adolescent emotional distress and self-harming behavior with: Subconscious Energy Healing Therapy (SEHT)

This case study examines the effectiveness of Subconscious Energy Healing Therapy (SEHT) in treating a 20-year-old female presenting with depressive symptoms, self-harming behaviour, and low self-esteem. SEHT, integrating Emotional Freedom Techniques (EFT) with psychospiritual principles, was employed to address her emotional distress and maladaptive coping mechanisms. The patient, "Miss K," exhibited significant emotional and behavioural challenges rooted in childhood bullying, family dynamics, and self-doubt. Through a structured approach, SEHT facilitated mindfulness, emotional release, and self-empowerment. A 2-step stress management framework emphasized awareness of stress responses and release through self-suggestions and tapping. Therapy outcomes included reduced self-harming behaviour, enhanced self-esteem, and improved academic focus. By incorporating personalized affirmations and spiritual elements, Miss K cultivated resilience, utilizing gratitude and Divine connection as healing tools. After five sessions, she demonstrated measurable improvement, including better academic performance and emotional stability. SEHT's holistic approach underscores the potential of integrating psychological and spiritual modalities to address complex mental health challenges. This case highlights SEHT's application as an adjunctive therapy for managing adolescent emotional distress. This case study explores the application and effectiveness of Subconscious Energy Healing Therapy (SEHT) in treating a 20-year-old female, "Miss K," who presented with depressive symptoms, self-harming behaviour, and low self-esteem. SEHT, an integrative modality combining Emotional Freedom Techniques (EFT) with psychospiritual principles, was utilized to address the underlying emotional distress, maladaptive coping mechanisms, and unresolved trauma from childhood bullying and adverse family dynamics. A structured therapeutic framework was employed, emphasizing mindfulness, emotional release, and self-empowerment. The therapy incorporated a 2-step stress management model: recognizing stress responses and utilizing self-suggestions and tapping to release negative emotions. Personalized affirmations, spiritual practices, and gratitude exercises fostered a deeper sense of resilience and connection to a higher power. These interventions aimed to reframe her self-perception and in still healthier coping strategies. Over the course of five sessions, Miss K demonstrated significant improvement across multiple domains. Observable outcomes included cessation of self-harming behaviours, enhanced self-esteem, and improved academic performance. She exhibited greater emotional stability and reported utilizing gratitude and spiritual practices as tools for ongoing self-regulation. This case underscores SEHT's potential as a holistic and adjunctive therapeutic approach for addressing complex adolescent mental health challenges.

3D Shape Control of Printed Micro‐Electrodes with Substrate Reshaping

AbstractAdditive manufacturing (AM) techniques based on liquid precursors, including inkjet printing or laser‐induced forward transfer (LIFT), are emerging as the tool‐of‐choice for the on‐demand fabrication of printed electronic devices on flat and flexible substrates. However, the aspect ratio of the printable structures, which is key for determining electrical properties, is typically determined by the wettability between printed ink and substrate. Higher aspect‐ratio structures can only be achieved by multi‐pass printing, with the consequent loss of fabrication throughput and increase in complexity. Here, these issues are addressed by using print‐n‐release, a method based on printing micro‐electrodes on pre‐stretched elastomeric substrates. Upon stress release, the liquid‐printed electrodes shrink while increasing their aspect‐ratio. As a result, their final shape can be tailored beyond the limitations imposed by wetting constraints, enabling intentional miniaturization by design. The principle and practical implementation of print‐n‐release are described, and show how electrodes with up to an 8 fold increase in aspect‐ratio and a 4 fold reduction in sheet resistance can be produced in a single‐pass compared to traditional printing methods. As a proof‐of‐concept, functional interdigitated electrodes that serve as sensors for drop volume and electrolyte concentration, delivering enhanced sensitivity and a reduced footprint not achievable with standard printing techniques are fabricated.

The adverse effects of nanosilver on fish gills: A critical review on ecotoxicity and underlying mechanism.

The environmental safety and health impacts of nanosilver have attracted much attention due to their continuous detection in water. Although the effects of nanosilver on aquatic organisms have been reported, the ecotoxicity and underlying mechanism of nanosilver in aquatic organisms are not fully understood. Fish gills are the primary target organs of pollutant exposure in aquatic environments, and is important to clarify the impact of nanosilver on aquatic organisms by systematically and comprehensively revealing the effect of nanosilver on fish gills. Here, we review the ecotoxicity and potential mechanisms of nanosilver on fish gills. Studies have shown the most commonly used and toxic nanosilver for studying the effects of nanosilver on fish gills is 5-30 nm. Nanosilver mainly affects various physiological functions of fish gills, such as respiration, ion, and osmotic pressure regulation, by disrupting the structure and components of tissues or cells (e.g., cell membranes and mitochondria), as well as interfering with tissue lipid, amino acid, and carbohydrate metabolism. The main mechanisms of toxicity induced by nanosilver in fish gills are gill membrane damage, oxidative stress, and silver ion release. This review provides a scientific basis for the detrimental effects of nanosilver on aquatic ecological environment health and the protection of fish resources.

Correlated Molecular Motion during Release of Residual Stress in Polymer Glassy Films.

Correlated molecular motion during the process of residual stress release in polymer glassy films is studied at the single-molecule level. Using poly(n-butyl methacrylate) (PnBMA) and poly(vinyl acetate) (PVAc) as the model polymers, thin films fabricated by spin-casting without thermal annealing were chosen as samples for investigation. Single-molecule fluorescence defocused microscopy was used to track the rotational motion of the fluorescent probes doped inside the polymer films. Under the activation effect of residual stress at experimental temperatures, the rotational motions of individual probes are discovered to be correlated a few degrees below the glass transition temperature (Tg), by analyzing the cross-correlation function of the rotational trajectories of different probes. Detailed investigations into the dependence on residual stress strength, intermolecular distance, probe-polymer interaction, and molecular orientation have been conducted. The results have revealed that the physical mechanism of the motion correlation is the randomization process from the state with preferred molecular orientation and presumably the polymer chain stretching.

Thermal Stability of Residual Stress, Microstructure, and Mechanical Property in Shot-Peened CNT/Al-Cu-Mg Composites

To investigate the thermal stability of a shot-peened specimen and ensure the reliability operation under high temperatures, CNT/Al-Cu-Mg composites were treated by shot peening (SP) and the isothermal aging treatment. The heating temperatures were 100, 150, 200, and 250 °C. Changes in surface residual stress and the distribution along the depth were investigated. The microstructure changes were analyzed by XRD and observed by TEM. Changes in mechanical properties were characterized by microhardness. The results show that the compressive residual stress (CRS) release and the microstructure changes mainly occurred at the initial stage of heating treatment. After 128 min of isothermal aging treatment at 250 °C, the surface CRS released 91.9% and the maximum CRS released 80.9%, the surface domain size increased by 222%, and the microstrain and microhardness decreased by 49% and 27.3%, respectively. The reinforcement effect introduced by SP basically disappeared. A large number of second-phase particles, such as CNT, Al2Cu, and Al4C3, were anchored at grain boundaries, hindering dislocation movement and enhancing the thermal stability of the material. Isothermal aging treatment at 100 °C and 150 °C for a duration of 32 min is a reliable circumstance for maintaining SP reinforcement.

How many syllables do you hear? Korean perception of English coda plosives

AbstractThis study investigates the direct perception of foreign structures in loanword phonology, concentrating on whether Korean listeners unnecessarily perceive an illusory vowel after a word-final plosive of English since a word-final voiceless plosive is permissible in their native language. In a syllable counting experiment, Korean participants listened to English nonce forms ending in a plosive and they indicated the number of syllables in each word. This study examined six different linguistic factors that may contribute to the perception of loanword borrowers including release, voicing and place of coda plosive, vowel tenseness, final stress and word size. The current results show that Korean listeners do perceive an extra syllable when the English pseudoword ends in a released plosive or in a syllable containing a tense vowel. This finding supports the hypothesis of adaptation in perception that unmotivated vowel insertion results from the misperception of English words rather than from a production grammar maintaining perceptual similarity between the English form and Korean pronunciation.

Role of Redox Homeostasis in the Communication Between Brain and Liver Through Extracellular Vesicles.

Extracellular vesicles (EVs) are small, membrane-bound particles secreted by cells into the extracellular environment, playing an increasingly recognized role in inter-organ communication and the regulation of various physiological processes. Regarding the redox homeostasis context, EVs play a pivotal role in propagating and mitigating oxidative stress signals across different organs. Cells under oxidative stress release EVs containing signaling molecules that can influence the redox status of distant cells and tissues. EVs are starting to be recognized as contributors to brain-liver communication. Therefore, in this review, we show how redox imbalance can affect the release of EVs in the brain and liver. We propose EVs as mediators of redox homeostasis in the brain-liver axis.

Effects of overconsolidation on seismic rock physics — A comparative study between unconsolidated sands and weakly cemented sandstone

In seismic rock physics, models typically assume rocks are normally consolidated, often neglecting the effects of overconsolidation. Recent studies reveal that overconsolidated sands, resulting from stress release, show different physical property variations than normally consolidated sands. However, similar research is lacking for weakly cemented sandstones, a common reservoir analog. This study aims to systematically compare the effects of overconsolidation and stress direction on unconsolidated sandstones and weakly cemented sandstones. It also assesses the impact of overconsolidation on seismic interpretation, monitoring, and rock-physics modeling applied to these two types of rocks. Experimental measurements of porosity, P-wave, and S-wave velocities were collected under different stress paths between loading and unloading. For weakly cemented sandstone, well-log data from the Norwegian Sea and Barents Sea were compared with experimental data. Analyses focused on the velocity-porosity relationship, [Formula: see text]/[Formula: see text] ratio versus AI, and [Formula: see text]/[Formula: see text] ratio versus effective stress. Results show that overconsolidation and stress direction affect these attributes differently in both rock types. The [Formula: see text]/[Formula: see text] ratio of unconsolidated sand remains stable under stress changes, whereas weakly cemented sandstone shows significant variation. Rock-physics modeling suggests that the stress sensitivity of the [Formula: see text]/[Formula: see text] ratio in overconsolidated weakly cemented sandstone under saturated conditions depends on the extent of cement deterioration. Strong cement deterioration upon unloading increases stress sensitivity, whereas less destructive deterioration decreases it. Experimental data align with models assuming strong deterioration, whereas field data from uplifted areas fit models assuming less destructive deterioration. This work highlights the importance of considering overconsolidation in rock-physics models and reveals pitfalls in applying existing models and workflows to overconsolidated reservoir rocks.

A Study of Seismic Cycles of the Strongest Earthquakes in Subduction Zones by Satellite Geodesy Methods

The work is devoted to modeling and studying geodynamic processes occurring in the vicinity of focal zones of the strongest (M ≥ 8) subduction earthquakes at different stages of the seismic cycle based on satellite geodetic data. The processes of preparation and realization of a number of powerful events that occurred in the Kuril–Kamchatka, Chilean, Japanese, and Aleutian subduction zones at the beginning of the 21st century were studied. Apparent spatial relationships have been identified between geodynamic processes occurring at different stages of the seismic cycle. It is shown that structural inhomogeneities of the medium have a direct impact on the processes of accumulation and release of elastic stresses.

Dual-interface passivation to improve the efficiency and stability of inverted flexible perovskite solar cells by in-situ constructing 2D/3D/2D perovskite double heterojunctions

Perovskite solar cells (PSCs) have demonstrated considerable potential as a promising photovoltaic technology. Nevertheless, the continued advancement is impeded by the presence of interfacial defects, which give rise to nonradiative recombination and ion migration. In this work, we demonstrate a simple and effective method to in-situ construct 2D/3D/2D perovskite double heterojunctions for effective passivation of defects and mitigation of ion migration in 3D perovskites. As a result, the inverted double-heterojunction PSCs exhibited a high power conversion efficiency (PCE) of 24.08 % with a low VOC loss of 0.37 V due to the minimal nonradiative recombination by dual-interface passivation. The stability of double-heterojunction devices has been significantly improved, maintaining 92 % of the initial value after 3000 h of storage under indoor light in a N2 atmosphere. Especially, the 2D/3D/2D perovskite double heterojunctions are applicable to flexible PSCs (FPSCs) to enhance both PCE and mechanical stability by effective residual stress release. Consequently, the FPSCs demonstrated a PCE of 21.58 % while retaining 86 % of the initial PCE even after undergoing a multi-cycle bending test for 10,000 cycles.

The Effect of Cyclic Heat Treatment on the Microstructure and Mechanical Properties of 18CrNiMo7-6 Gear Steel.

To avoid grain coarsening resulting from high-temperature carburizing, the effects of cyclic quenching and tempering on the microstructure and mechanical properties of 18CrNiMo7-6 gear steel were investigated. Three groups of samples were compared, which went through 0/1/3 times of quenching-tempering cycles after initial pseudo-carburizing. The variations in grain size, hardness, tensile strength, and toughness were systematically assessed using a series of experimental techniques. The experimental results indicate that the austenite grain size decreases from 14.8 μm to 5.0 μm as the number of cycles increases, accompanied by improved grain uniformity, which is beneficial to fine-grain strengthening mechanisms. During the phase transition, defects in the original martensite structure are transferred to the newly formed austenite, with the energy stored during the martensitic-to-austenitic transformation driving the grain refinement process. However, after several cycles of quenching and tempering, the release of some residual stresses and dislocations reduces the driving force for recrystallization, limiting further grain refinement. Although the strength decreased slightly after three cycles due to a reduction in dislocation density, toughness increased to a maximum of 172 J/cm2, primarily due to the enhancement of grain refinement and grain boundary density, which effectively hindered crack propagation. This study confirms the efficacy of cyclic heat treatment in refining grain structure and improving both strength and toughness, thereby contributing valuable insights to the research and development of high-performance gear steels.