Internal Pressure Research Articles

Mechanical Properties and Fire Resistance of 3D-Printed Cementitious Composites with Plastic Waste

The study focuses on the development of cementitious composites using 3D printing and plastic waste as a sustainable aggregate substitute. This study involves experimenting with various percentages of plastic waste as a partial substitute for ground granulated blast furnace slag (GGBFS) in a control mix. The study examines the anisotropy of the 3D printing process, comparing it with properties of mold-cast samples. In addition, it assesses the fire resistance and mechanical properties of samples at elevated temperatures (100 °C, 300 °C, and 600 °C). Key mechanical properties, including 28-day compressive stress and flexural strength, are determined through experimental testing using a standard compression test and three-point bending test. The study also considers the modulus of elasticity (MOE) in compressive tests to evaluate a sample’s ability to deform elastically and the flexural toughness index to assess energy absorption and crack resistance of flexural samples. Following the experimental testing, the study’s key findings suggest that significant mass loss occurred at 300 °C and above, with plastic samples demonstrating increased mass loss at 600 °C. At 600 °C, plastic degradation led to the formation of voids and cracks within samples due to heightened internal pressure. Anisotropy was evident in 3D-printed samples, with loads parallel to the layer direction resulting in greater compressive strength and MOE. Furthermore, layer direction parallel to the longitudinal axis of flexural samples yielded higher flexural strength and flexural toughness. Mold-cast samples displayed superior compressive strength and stiffer behavior, with higher MOE compared to 3D-printed samples. However, 3D-printed plastic samples exhibited superior flexural strength compared to mold-cast samples, attributed to the alignment of plastic within the samples. The study also observed a reduction in compressive strength with the addition of plastic, explained by the poor bonding of plastic with cement due to its hydrophobic nature. Despite this, flexural strength generally improved with plastic addition, except at 600 °C, where plastic samples showed significant degradation in both compressive and flexural strength due to plastic degradation within the samples.

Feasibility study of FFPP thermoplastic lining for concrete pipeline rehabilitation: a case study

This study investigates the feasibility and efficacy of Flexible Fiber-reinforced Polypropylene (FFPP) thermoplastic lining technology for the rehabilitation of concrete pipelines, specifically focusing on BONNA pipes. A custom-built test bench, featuring a 2-m high platform and multiple 90° bends, was designed to simulate the impact of pipe gallery space, adaptability and material accessibility of bent pipes, and cooling issues of long-distance dragging of materials. The simulation process utilizes a modified polyvinyl chloride (PVC) liner with unique thermomechanical properties. The liner, folded into an "H" shape, is mechanically inserted into the host pipe using a 2-ton winch and pulley system. During insertion, continuous high-temperature steam injection softens the material, facilitating expansion and conformity to the pipe's internal surface. Subsequently, cold air application rigidifies the liner below 60 °C while maintaining pressure, ensuring structural integrity and adherence to the pipe wall. Results revealed that while the FFPP liner successfully navigated through confined spaces, including a 300 mm expansion joint, spatial constraints led to localized cracking defects during inflation. Traction feasibility tests using a 2-ton winch demonstrated high pulling resistance in sections with multiple bends. The liner exhibited excellent adhesion in straight pipe sections but showed significant wrinkling and poor adhesion in 90° bends. Notably, the liner demonstrated remarkable strength, withstanding internal pressures exceeding 3.3 MPa in a DN300 pipe with a 10 cm diameter intentional defect, far surpassing the on-site hydrostatic test pressure of 9 bar. This study addresses a significant gap in trenchless rehabilitation research by evaluating the FFPP thermoplastic lining technique in complex pipeline geometries, an area previously understudied. While the technique shows promise for structural reinforcement in straight pipe sections, our findings reveal that its application in complex pipeline geometries requires further refinement. The study contributes to the field of trenchless pipeline rehabilitation in several ways: (1) it provides empirical data on FFPP liner performance in multi-bend configurations and confined spaces, (2) it identifies specific challenges such as localized cracking and poor adhesion in bends, and (3) it demonstrates the liner's exceptional strength under high pressure conditions. These insights advance our understanding of FFPP technology's potential and limitations in concrete pipe repair, paving the way for future research and development in optimizing trenchless rehabilitation techniques for complex pipeline systems.

Structural behavior of triple-layer composite lining of a water conveyance tunnel: Insight from full-scale loading tests

When constructing water conveyance shield tunnels under high internal pressure, composite linings are preferred over single-layer segmental linings due to the superior water tightness and load-bearing capacity. A triple-layer composite lining, consisting of an outer segmental lining, internal steel tube, and self-compacting concrete (SCC) filling, has recently been applied in a large-scale water conveyance tunnel project in China. However, its structural behavior under external overburden and internal water pressures remains poorly understood. This study investigates the mechanical behavior of the triple-layer composite lining through full-scale loading tests using a novel platform that simulates external and internal pressures. Results show that the composite lining remains highly elastic under combined loads with an internal pressure of 0.4 MPa. When the internal pressure increases to 0.6 MPa, cracks first appear in the SCC layer near segment joints, propagating uniformly and leading to stress redistribution. Studs on the steel tube-SCC interface strengthen bonding, reducing debonding at this interface while slightly increasing debonding at the SCC-segment interface. Despite localized SCC damage, the lining maintains excellent serviceability under cyclic pressure fluctuations. This study offers valuable insights for the design and construction of water conveyance shield tunnels with triple-layer composite linings, particularly in high-pressure environments.

Pressure characteristics and force analysis of pump turbine in variable-pressure outlet pump mode

A nonstationary numerical simulation was performed on the outlet pressure stabilization and periodic variable-pressure condition of a pump turbine model in the pumping condition. The objective was to dissect the flow mechanism and force characteristics of components within the outlet variable-pressure pumping condition of the pump turbine and to probe into the stability of the pump turbine under such working conditions. Additionally, the alterations in the runner state, pressure distribution, pressure pulsation, as well as the forces exerted on the runner and top cover during this process were analyzed. The results demonstrated that the internal pressure and flow pattern of the pump turbine under variable-pressure conditions fluctuated periodically in accordance with the outlet pressure. An augmented frequency of the outlet pressure variation led to an elevation in the amplitude of the internal pressure change. Nevertheless, a hysteresis difference was observed in the changes of the flow channel pressure and flow pattern. The pressure pulsation in the runner area was influenced by the runner rotation, static and dynamic interferences in the lobe-free area, and the unsteady flow induced by the alterations in the outlet pressure.

Study on stress concentration and fatigue life of tubing with slip indentation

The indentation caused by slip on the outer wall of tubing is a significant contributor to stress concentration and, consequently, fatigue failure in the tubing string. Through an analysis of the interaction between slips and tubing, a mathematical model to predict slip-tubing interaction and slip crushing load is formulated, accounting for external pressure, internal pressure, and axial forces. On this basis, the influence factors and influence rules of slip crushing load are studied, and three-dimensional yield surface and tri-axial stress ellipse of tubing are investigated, considering different transverse load factors and design factors. To accurately forecast the fatigue life of tubing subjected to slip indentation, two models are established: one for fatigue life prediction and the other for tubing string vibration. In order to quantitatively assess the stress concentration arising from slip indentation, a finite element model of tubing featuring slip indentation is established. Finite element analysis reveals that stress concentration and non-uniformity are evident in the vicinity of slip indentation, with their severity intensifying as the indentation depth grows. The initial step in assessing fatigue life involves fatigue life tests on tubing material subjected to varying stress levels. Subsequently, a case study is conducted and the variations of wellhead pressure and axial stress are evaluated. Fatigue life analysis reveals that the fatigue life is notably sensitive to variations in stress amplitude and slip indentation depth. An increase in the magnitude of alternating stress and the depth of slip indentation will result in a significant reduction in the fatigue lifespan. The methodologies employed in this research, along with the resulting findings, offer a robust theoretical framework and a solid practical basis for forecasting and managing stress concentration and fatigue durability in tubing affected by slip indentation.

Experimental and Numerical Simulation on the Generation and Development of Cumulative Plastic Strain of Cement Sheath in Salt Cavern Gas Storage Well

ABSTRACTSalt cavern gas storage is an important technical means to balance the demand for staggered energy supply. Due to the repeated injection and extraction of natural gas in gas storage facilities, sealing integrity failure in the wellbore of gas storage facilities frequently occurs. In response to this, considering the cyclic loading and unloading of the pressure load inside the casing, mechanical tests of set cement were carried out under alternating loads, quantifying the cumulative plastic strain change law of set cement and revealing the deterioration characteristics of its mechanical properties. A numerical model of cumulative plastic strain of casing cement sheath formation under alternating load was established based on the obtained experimental parameters. Comparative verification was conducted using experimental data, and the variation law of cumulative plastic strain of cement sheath was analyzed. The distribution of cumulative plastic strain on the cement sheath bonding surface of the entire wellbore was quantified. The research results indicate that the higher the internal pressure value of the casing, the earlier the plastic strain appears, and with the increase in the number of alternating loads, the cumulative plastic strain increases approximately linearly. After the internal pressure increased by 30 MPa, the cumulative plastic strain increased by a maximum of 46.75%. When the number of loading and unloading cycles under alternating loads is small, reducing the elastic modulus (6 GPa) of the cement sheath can effectively reduce its cumulative plastic strain. However, as the number of loading and unloading cycles under alternating loads exceeds a specific value, the cumulative plastic strain produced by high elastic modulus (15 GPa) cement sheaths decreases. Finally, the distribution pattern of cumulative plastic strain along the wellbore under different gas injection times and complex formation conditions was analyzed. Suggestions for establishing well barriers in salt cavern gas storage during cementing were proposed. The research results can provide theoretical and engineering references for evaluating the sealing integrity of gas storage wells.

Effect of internal pressure and loading path on deformation behavior during low pressure tube hydro-pressing

To overcome the limitations of hydro-pressing process with either linear increasing pressure loading path or constant pressure loading path, a hydro-pressing process with two steps pressure loading path was proposed and an experiment was conducted on hydro-pressing process of DP590 steel tubular part with varied rectangular-section perimeters. The effects of internal pressure and loading path on cross-sectional shape and stress distribution were discussed. An analysis was conducted to give the critical punch stroke of the first step, and an optimal loading path was put forward. The pressure loading path was divided into two steps, the result indicates no buckling happens even no internal pressure adopted in the first step. The wall thickness distribution of the tubular part formed under two steps pressure loading path is more uniform than that with constant pressure loading path. Mechanical analysis proves that the flexural modulus of the tube wall in the earlier stage of deformation is high enough due to the short length of the straight side, which is no need for supporting pressure. Under a reasonable loading path, a rectangular-section tubular part with a compression ratio of 5 % was obtained with lower pressure 13.5 MPa. Its relative corner radius is only 1.5, which exceeds the limiting value of that formed by conventional tube hydroforming.

Application of porous luffa fiber as a natural internal curing material in high-strength mortar

This study explores the potential of renewable plant fibers as internal curing (IC) materials, analyzing their potential in high-strength mortar (HSM) applications. Experiments involving the incorporation of different volumetric ratios of luffa fiber into concrete assessed impacts on autogenous shrinkage (AS), mechanical properties, and microstructure. The research found that the addition of luffa fibers extended both the setting times of the mixture, and after final setting, continued the hydration reaction by releasing internally stored water. Compared to the control group, luffa fibers significantly reduced AS by up to 56.87%, primarily due to their high-water absorption capacity (211%), which mitigates the internal capillary pressures during the cement hydration process. Moreover, the inclusion of luffa fibers significantly affected the concrete's mechanical properties: a 1% luffa addition enhanced the compressive strength at 28 days by 7.6% over the control; concrete with 2% luffa fiber exhibited the highest flexural strength at 28 days, showing a 9.4% increase over the control. Microstructural analysis revealed that luffa fiber not only promoted continued hydration but also increased the content of hydration products and enhanced the compactness of the cementitious matrix. Overall, luffa fibers effectively reduce HSM’s AS and enhance its mechanical properties and microstructure, showing potential to improve concrete performance.

Towards a refined insight into physical education teachers’ autonomy-supportive, structuring, and controlling style to the importance of student motivation: a person-centered approach

ABSTRACT Background: Physical education (PE) teachers face the challenge of managing their classroom and directing students’ learning in a way that engages students in a motivating manner. For this reason, numerous studies have examined the impact of PE teachers’ autonomy-supportive, structuring, and controlling style. Most research relied on a variable-centered approach, but a person-centered approach is warranted as in reality these styles co-occur. Prior person-centered research examined the combinations of autonomy support and structure, autonomy support and control, and structure and control. In the current study we take the next step by examining combinations of the three most prevalent styles in PE teachers. This investigation is particularly relevant as many PE teachers believe that being perceived as controlling might not be detrimental if they are also seen as autonomy-supportive and/or structuring. Purpose: To further understand the interplay of an autonomy-supportive, structuring, and controlling style, this study simultaneously investigated all three styles using a person-centred approach. The first aim was to examine how students perceive PE teachers’ combined use of an autonomy-supportive, structuring, and controlling style. The second aim was to investigate whether students’ motivation differed according to the profile they perceived their teacher to be in. Method: A sample of 673 secondary school students (M age = 13.82, SD = 1.25 years) reported on their PE teachers’ autonomy-supportive, structuring, and controlling style, and their motivation for PE. Hierarchical K-Means Cluster analyses and MANCOVA tests were performed. Findings: Results showed that in the eyes of the students, PE teachers employed different combinations of autonomy support, structure, and control to different degrees, as six different profiles were found. Students who perceived their teacher as more need-supportive displayed higher levels of intrinsic motivation, integrated, and identified regulation, particularly when students perceived their teacher as high on both autonomy support and structure. In contrast, students who perceived their teacher as more controlling displayed more extrinsic regulation and amotivation, even when students simultaneously perceived their teacher as need-supportive. Students who perceived their teacher as higher on all three styles displayed higher levels of introjected regulation, suggesting that this mixture of styles elicits internal pressure. Conclusion: In conclusion, according to the students, PE teachers can combine certain autonomy-supportive, structuring, and controlling behaviors to different degrees, indicating that classifying PE teachers as either need-supportive or controlling may be inaccurate. Students who perceived their PE teacher as highly autonomy-supportive and structuring and lowly controlling reported the most optimal motivational outcomes. The detrimental effect of a perceived controlling style was evident, even when the teacher was additionally perceived as autonomy-supportive and structuring. This finding challenges the common belief among PE teachers that being perceived as controlling is not harmful when simultaneously being perceived as autonomy-supportive and controlling. Interestingly, both need-supportive and controlling styles were positively related to students’ introjected regulation.

Numerical study of paste-bridge transfer process for laser induced high-viscosity silver paste

Laser-induced forward transfer (LIFT) is promising for solar-cell metallization and electronic printing due to its low dependence on paste viscosity and nozzle-free process. In this paper, the transfer process and morphological characteristics for LIFT of high-viscosity silver paste were studied through simulations and experiments. The shear-thinning rheological properties were considered using the fitted Carreau model. Variations of paste protrusion with single pulse energy and time were obtained from the high-speed imaging. The evolution of initial pressure that induces the paste protrusion was solved inversely and quantitatively expressed by a polynomial function. The internal pressure should be sufficiently larger than 40 MPa to induce the effective transfer. In the simulation, the induced bubble undergoes a non-spherical transition from mushroom to pea-pod and capsule shapes due to constraints from surrounding paste and substrate. The deposition morphology formed by the induced mushroom-shaped bubble shows high printing precision with thin width (<30 μm) and large height (∼10 μm). The simulated diameter and height of transferred single voxel agree with those from experimental measurement. It can gain insight into the transfer dynamics of high-viscosity pastes and provide process optimization for precision printing of voxels by LIFT.

Sitting pressure during wheelchair propulsion and handcycling: effects of backrest angle, movement intensity and cushion type

Purpose: The main aim of this study was to compare sitting pressure (peak pressure index (PPI) and peak pressure gradient (PPG)) between a daily wheelchair and fixed-frame handcycle, thereby assessing the effect of handcycle backrest angle, movement intensity and cushion type. Materials and methods: Twenty able-bodied participants performed static and dynamic (two intensities) tests in a wheelchair and handcycle. A honeycomb wheelchair cushion and standard foam handcycle cushion were used. Handcycle backrest angles were 45° and 60°. The PPI and PPG at the sacro-coccygeal (SC) and ischial tuberosity (IT) regions were determined with a pressure mat. Results: PPI at the IT-region was higher in the 60° handcycle condition than in the wheelchair (p = 0.04), while PPG at the IT-region did not differ significantly between the wheelchair and handcycle conditions (p > 0.05). PPI and PPG were higher at the 45° handcycle SC-region compared to the wheelchair IT-region (p < 0.03). PPI and PPG at the IT-region were higher with the 60° than with the 45° backrest angle (p < 0.01), while at the SC-region PPI was higher with the 45° backrest angle (p = 0.047). No clear influence of movement intensity was found. PPI and PPG at the IT-region and PPI of the SC-region in the handcycle were significantly lower with the wheelchair cushion than with the handcycle cushion (p < 0.01). Conclusion: Overall, sitting pressure was higher in the handcycle compared to the daily wheelchair. For handcyclists using an upright position, it is recommended to use a cushion designed to redistribute pressure, thereby reducing internal tissue pressure and shear.

Thermodynamic properties of pinned nanobubbles.

We present molecular dynamics simulations to study the thermodynamics of nanobubbles trapped at the mouth of narrow slit pores. Except when the slit dimensions are comparable to typical molecular sizes, the predictions of macroscopic thermodynamic theory are recovered by our simulations. Our simulations confirm that in this case, the internal pressure of stable nanobubbles is independent of the bubble radius and the surface tension and only depends on the bulk properties of the solute-containing solution, i.e., the chemical potential balance. However, in the case of extreme confinement, the pressure is not a suitable quantity to describe the thermodynamics of the bubbles, while the balance of the chemical potentials is.

An Investigation of Parameter Sensitivity and a Dynamic Analysis of Subsurface Storage Chambers Utilizing the Finite Difference Method

Underground compressed air energy storage chambers are a promising emerging energy storage technology with strict limitations relating to the stability of the surrounding rock. This study conducted displacement and plastic zone analyses during the excavation and stabilization phases of the chamber utilizing the finite difference method based on engineering data, demonstrating that the stability of salt rock can effectively withstand internal pressures ranging from 0 to 9 MPa, with an average of 15 mm in the Z-axis and 19.23 mm in the X-axis. To further investigate the feasibility of subterranean energy storage reservoirs, the FOS for various surrounding rocks was calculated at different burial depths. These results facilitated a parameter sensitivity analysis on the stability of the surrounding rock of the underground energy storage reservoir. The dynamic reaction of the underground chamber was studied using synthetic seismic wave technology, demonstrating that the seismic capacity of the structure adhered to the code, and the post-seismic displacement remained within the safe range (Z-axis 34 mm, horizontal 19 mm). The results demonstrate the stability analysis method of the chamber and establish a foundation for the extensive implementation of CAES which will contribute to the development of energy storage technology.

Low displacement effects of using internal pressure relief blade in cement deep mixing

Low displacement effects of using internal pressure relief blade in cement deep mixing

Concentric Compressive Behavior and Design of Stainless Steel–Concrete Double-Skin Composite Tubes Influenced by Dual Hydraulic Pressures

The external hydraulic pressure and internal medium pressure acting on submarine pipelines can lead to the coupling effect of active and passive constraints on the mechanical performance of steel–concrete double-skin composite tubes, resulting in a significantly different bearing capacity mechanism compared to terrestrial engineering. In this paper, the full-range concentric compressive mechanism of new-type stainless steel–concrete double-skin (SSCDS) composite tubes subjected to dual hydraulic pressure was analyzed by the finite element method. The influence of geometric–physical parameters at various water depths was discussed. The key results reveal that imposing dual hydraulic pressures significantly improves the confinement of double-skin tubes to encased concrete, resulting in a higher axial compressive strength and a non-uniform stress distribution; increasing the material strengths of concrete, outer tubes and inner tubes results in an approximately linear enhancement in axial bearing capacity; enhancing the diameter-to-thickness ratios of outer tubes and inner tubes can decrease the bearing capacity of SSCDS composite tubes; and the axial compression strength of SSCDS composite tubes with a higher hollow ratio of 0.849 tends to decrease with increasing outer hydraulic pressure. A practical method that integrates the effects of dual hydraulic pressures was developed and validated for the strength calculation of SSCDS composite tubes. This research provides fundamental guidelines for the application of pipe-in-pipe structures in deep-sea engineering.

Ballistic response of an airbag with parallel ribs under spherical projectile impact

The airbag-type inflatable structure with ribs was developed, composited from thermoplastic polyurethane (TPU) membranes. Ballistic impact tests were conducted on pre-inflated airbags to assess the airbag’s dynamic response. A set of Split Hopkinson Tensile Bar (SHTB) experiments were conducted on TPU membranes at strain rates ranging from 3000 to 12,000 s−1 to derive a strain-rate dependent constitutive model for TPU under ballistic impact conditions. Based on the fluid cavity inflation method, a finite element model was employed to analyze the structural response of the airbag. Based on the principle of energy conservation, an innovative theoretical model for the impact of airbags considering internal pressure has been established. The results indicate a strong agreement between the numerical, theoretical, and experimental results concerning the impact process and ballistic limit. It was observed that as the internal pressure rises, the ballistic limit of the airbag decreases. The theoretical model indicates that with an increase in internal pressure and the spacing of the center ribs, the initial strain energy of the membrane increases, leading to a decrease in the kinetic energy dissipation of the airbag to the projectile and subsequently reducing the ballistic limit of the airbag. This research provides a theoretical foundation and basis for the structural design and analysis of energy dissipation patterns in inflatable structures. It expands the potential applications of inflatable composite structures in the field of ballistics.

A comprehensive analysis of preload force effects on the opening of safety valves and thermal runaway behavior in prismatic batteries

Lithium-ion batteries (LIBs) are typically assembled into battery packs under a preload force. Despite its significance, research on the impact of preload force on thermal runaway (TR), a critical safety concern for LIBs, remains deficient. Furthermore, few existing TR models incorporate preload force, highlighting a gap in current methodologies. In this work, a TR prediction model that integrates gas generation and mechanical responses is developed, aiming to incorporate the influence of preload force and enhance the accuracy of safety venting predictions. To validate the prediction model, TR experiments are conducted to examine the internal pressure and shell deformation of LiFePO4 (LFP) prismatic batteries under different preload forces. The experimental results reveal that an increased preload force leads to a higher internal pressure. The increase rate of internal pressure in the rapid rise stage is about 0.5 kPa/s, regardless of the preload force. Moreover, model results indicate that an excessively high preload force leads to a reduction in the opening pressure of the safety valve, due to the large stress concentration at the safety valve. Overall, this study can provide a comprehensive guide for the safety design of prismatic battery systems, advancing current standards.

Politicising energy transitions: the political economy of reducing dependence on coal in South Africa’s minerals energy complex

ABSTRACT Proposals to reduce South Africa’s dependence on coal-generated electricity have repeatedly stalled despite growing internal and international pressure to decarbonise electricity generation. Where there is a growing body of scholarship that identifies barriers to an energy transition in the country, studies that explore how these barriers emerge and are perpetuated are comparatively limited. This paper contributes to this scholarship by looking beyond the energy sector to analyse unresolved debates over how to achieve post-apartheid developmental goals influence access to – and the distribution of – government resources. The paper then shows how in the energy sector different actors use narratives around development to advocate for and oppose measures to restructure the national electricity company and increase procurement of privately generated renewable energy. As well as contributing to South Africa-specific scholarship, this paper provides insights into how resistance to western-funded energy transitions may emerge in other areas in the Global South.

A Multi-Scale Thermal-Mechanical Numerical Method for Mini-Channel Heat Exchanger Subjected to Fluid Pressure Loads

Abstract This study proposes a novel multi-scale numerical method for thermal-mechanical analysis of mini-channel heat exchangers (MCHEs) under internal fluid pressure and temperature loads. The method comprises a macro-scale model for global analysis and a meso-scale model for detailed submodel analysis, specifically focusing on the internal fluid pressure effects within the MCHEs. The macroscopic model divides the MCHE into cover plate and homogenized regions subjected to pressure and temperature loads. To incorporate internal pressures into the homogenized MCHE model, mathematical equations are formulated to convert internal fluid pressures into equivalent strain loads. Additionally, a novel equivalent thermal expansion method is introduced, integrating internal fluid pressure loads by prescribing equivalent thermal expansion coefficients alongside spatially-varying nodal temperature fields within the MCHE. The meso-scale models with detailed channel patterns are assigned to specific portions of the homogenized region. The integration of the mesoscale model into the macroscopic framework is achieved through the application of the submodel method. Comparisons between the equivalent and actual MCHE models show that the proposed equivalent method can provide accurate predictions for thermal-mechanical deformations and stresses, and significantly reduce the computational expenses.

Enhancing adolescent mental health through cognitive and social support: Insights from study on depression in Chinese adolescents.

Adolescent depression is a growing global health concern, affecting 14% of adolescents and leading to severe consequences such as academic failure, substance abuse, and suicidal ideation. The study by Yu et al, investigates the cognitive and social factors influencing depression in 795 Chinese adolescents. Findings reveal that negative life events (NLEs) and dysfunctional attitudes are strongly associated with depressive symptoms, while social support moderates the impact of NLEs but not dysfunctional attitudes. The study highlights the need for cognitive-behavioural interventions targeting perfectionism and autonomy, and the importance of strengthening social support systems in schools and communities. Culturally sensitive, holistic approaches to adolescent mental health are crucial for addressing both the internal vulnerabilities and external pressures contributing to depression. Further research is needed to explore the roles of peer and parental support and the long-term effects of these factors across diverse cultural contexts.