Varying Stress Levels Research Articles

Attentional focus modulates physiological response to arousal in a competitive putting task

Attentional focus during the execution of perceptual motor tasks has been shown to affect performance outcomes. The purpose of this study is to assess the physiological changes prompted by attentional focus in various levels of stress. Thirty-six healthy young males and females were randomized into groups and directed on attentional focus in a staged putting competition scenario intended to elicit competitive anxiety. External focus groups experienced less internal workload at all arousal levels and preserved heart rate variability measures when audiovisual distraction was introduced.

The elephant in the room: How personal and workplace traits shape role stress in the construction industry

Geographical regions shape workplace stress, as each location presents distinct environmental, cultural, and socioeconomic conditions. These regional variations contribute to varying stress levels among workers depending on their unique conditions. This study explored the effects of personal and workplace traits on the role stress of the construction workforce in the South Asian region. Data were collected through a cross-sectional survey involving 274 project-level personnel from ten construction companies in Sri Lanka. Factor analysis validated regression analysis was performed to identify the effects of personal and workplace traits on role stress. The results highlighted the significance of age, education level, and organization tenure in shaping role stress. Specifically, the increasing age was associated with decreased role overload and work-family conflict. A higher level of education was linked to a greater likelihood of experiencing role conflict. Extended organization tenure was found to decrease role ambiguity but increase role conflict and work-family conflict among construction project employees. These findings hold implications for shaping organizational policies aimed at improving employee well-being. By incorporating these insights, organizations can develop strategies that foster a more supportive and healthier work environment.

Factors Impacting Work-Life Balance and Quality of Work Life among Teachers

Introduction: A number of circumstances can disrupt the work life balance, and achieving success depends not only on one’s ability to perform at a high level but also on one's ability to manage professional and personal obligations. This study aims to explore the factors that impact stress levels and work life balance of teachers working in government-aided and self-financing schools. Method: A total of 200 samples were selected, and a structured questionnaire was adopted to gather the primary data. The collected data was tested by statistical analysis using various tools, including Mann-Whitney U test, Kruskal-Wallis test, Chi-square, and ANOVA for interpretation. Results: The findings indicate that teachers in government-aided schools experience lower stress levels and evince higher contentment across various dimensions in quality of work life. However, the teachers in self-financing schools grapple with varying stress levels, ranging from lower to higher stress, reflecting dissatisfaction across all aspects of life. Conclusion: A collective implantation of strategies from teachers and institutions is required to maintain a healthy and harmonious work life balance in order to augment the quality of work life.

The Level of Perceived Stress and Affecting Factors due to Current Economic Crisis Among Undergraduates in Faculty of Health-Care Sciences, Eastern University Sri Lanka

Abstract In 2021, the Sri Lankan government officially declared the worst economic crisis in the country. The ongoing economic crisis in Sri Lanka has been affecting the whole sector of the country. The undergraduate students who stayed in hostels had to suffer a lot due to restrictions of family income. The parents face difficulties in affording all expenses required by their children as university students. As a result, students had to cut down their daily expenditures. Due to this crisis, the students had to be affected by various levels of stress leading to disruptions in both physical and mental health. It also caused poor academic performance. Some students had to quit their studies. Stress is an emotional feeling affecting all ages and it appears at any time of the life cycle. The purpose of this study was to identify the level of perceived stress and affecting factors due to the current economic crisis among undergraduates in the Faculty of Health-Care Sciences (FHCS), Eastern University Sri Lanka (EUSL). A cross-sectional descriptive study was conducted using a self-administered online questionnaire to gather information and a complete enumeration was done. The Perceived Stress Scale (PSS) instrument was used to assess the severity of the undergraduate perceived level of stress-related current economic crisis. Demographic variables and affecting factors due to the current economic crisis were considered. The overall mean stress score in the study population was 22.91(SD=5.386). The majority of undergraduates reported moderate stress 70.8% (N=240). A multiple linear regression analysis was applied, Pearson correlation was used, and all necessary tests were performed. There was a statistically significant, positive correlation between the level of perceived stress and their family income per month (p=0.000). The contributing factors correlated with perceived stress were unable to enjoy meeting people, unable to frequently visit home, unable to take meals from outside and instead of cooking, trying to save extra expenditure money, unable to frequent shopping for dresses, cosmetics, jewelry. The level of perceived stress reported by the majority of the students was moderate. Mainly their family income per month contributed to stress among them. Policymakers and the university administration have to consider more about the stress levels of the students and plan suitable programs like scholarships to manage stress.

A pore network modeling approach to bridge void ratio‐dependent soil water retention and unsaturated hydraulic conductivity curves

AbstractIn geotechnical engineering, understanding the relationship between soil permeability and deformation is essential, particularly for applications like earth dams, where compaction‐induced permeability reduction is crucial for performance optimization. In unsaturated soils, soil moisture content significantly impacts hydraulic conductivity. Traditionally, changes in unsaturated hydraulic conductivity have been linked to soil void ratios. However, a pore network modeling perspective reveals the significance of structural parameters, such as pore and throat size distribution and pore coordination number. This study introduces a pore network model to estimate unsaturated hydraulic conductivity based on void ratio‐dependent soil‐water retention curves. It examines how soil deformation at varying stress levels affects structural parameters and the water phase continuity. The model shows strong potential in predicting unsaturated hydraulic conductivity across different stress levels, aligning well with experimental data and established equations. Notably, the aspect ratio and coordination number parameters are most affected by stress levels. The study also presents relationships to describe changes in pore network structural parameters with soil void ratio, which can be used to predict soil‐water retention curves and unsaturated hydraulic conductivity at various stress levels.

Study on creep performance of shotcrete lining for tunnels

Creep, as a long-term deformation characteristic of shotcrete, significantly influences the load-bearing performance and durability of tunnel support structures. This study conducted creep tests on shotcrete under varying stress levels. The results reveal that shotcrete exhibits linear creep response within the stress range of 30%–40%, while the critical stress range for nonlinear creep response occurs between 40% and 50%. Employing SEM-EDS and XRD analysis methods, the impact of accelerator on the microstructure evolution and creep mechanism of shotcrete is explored. The accelerator accelerates the hydration of C3S, promoting the generation of AFt and C–S–H gel, leading to rapid solidification of the matrix and enhanced early strength. With the consumption of SO42− ions, AFt gradually transforms into AFm, resulting in increased matrix porosity. This phenomenon contributes to the reduced later-stage strength and substantial creep deformation of shotcrete. Based on experimental outcomes, this study evaluates the applicability of existing creep calculation models to shotcrete.

Unraveling time-dependent roof stability dynamics in Iran's coal mines through laboratory-based rock displacement testing

Roof stability is a critical concern in coal mines, as the potential for roof collapse poses a significant risk to miners' safety and productivity. Roof stability is heavily influenced by the time-dependent properties of the rock mass above the workings. This study uses rock displacement testing to examine the effect of time-dependent properties on roof stability and resistance reduction in coal mines in Iran. The study employed laboratory-based rock displacement tests on samples collected from coal mines in Iran, subjected to varying stress levels over time, to simulate the gradual deterioration of rock mass strength in underground mining conditions. The samples were monitored for displacement under these conditions to quantify the reduction in roof resistance over time and assess its effect on roof stability. The study found that areas with high stress at equilibrium gradually fail with time, and the stress transfers from the failure zone into deeper solid rock. The results demonstrate that varying viscous parameters can lead to different relaxation behaviors and stress distribution. Furthermore, incorporating strength degradation into numerical simulation can capture the failure under creep conditions and improve the accuracy of predicting time-dependent roof failure. This research aims to enhance safety measures and reduce the risk of collapses by investigating the time-dependent properties of roof stability through rock displacement testing in Iran's coal mines. The study's innovative approach uses numerical simulation based on the viscoelastic-plastic model to simulate the time-dependent behavior of the rock and incorporate strength degradation into the simulation. The results provide valuable insights into the time-dependent behavior of rock mass in coal mines in Iran and contribute to developing strategies for improving roof stability and lessening the chance of roof collapses. The instantaneous elastic strain was 4.35 × 10–4, and creep simulation was activated to run for a time equivalent to 2 × 106 s.

Evaluation of fatigue characteristics of 3D printed/composites reinforced with carbon fiber using design of experiments

AbstractThis study investigates the fatigue characteristics of 3D‐printed composites made from polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS), reinforced with carbon fiber. It involves designing and building a rotating bending fatigue machine, creating standard specimens via FDM, and applying DOE using Taguchi method. Standard specimens are subjected to cyclic loading with a print orientation of 0°, 45°/−45°, and 90°, motor speed and load. Materials such as PLA, ABS, PLA‐CF, and ABS‐CF are tested by maintaining a consistent layer thickness of 0.16 mm and 99.99% infill density while varying stress levels. PLA‐CF outperforms PLA, ABS, and ABS‐CF in fatigue life, with 0° print orientation exhibiting superior fatigue strength. Statistical analysis underscores the significance of print direction, material composition, and stress level. Additionally, the study aims to construct S‐N curves for 3D‐printed PLA/ABS composites with carbon fiber reinforcement, advancing our understanding of mechanical properties and print parameter optimization for enhanced fatigue performance in 3D‐printed composites.Highlights Fatigue characteristics of 3D printed composites made from PLA and ABS, reinforced with carbon fiber investigated. Four polymer composites were used: PLA, ABS, PLA‐CF (short carbon fiber), and ABS‐CF (short carbon fiber). The research focused on the impact of 3D print orientation on fatigue properties, considering print angles of 0°, 45°/−45°, and 90°, alongside adjustable factor like motor speed and load. With a consistent layer thickness of 0.16 mm and 99.99% infill density, the fatigue tests were conducted under stress‐controlled conditions at varying stress levels. Results demonstrate that PLA‐CF specimens exhibit superior fatigue lifetimes compared to PLA, ABS, and ABS‐CF samples.

Simulation of concrete cracking and chloride diffusion under uniaxial compression

The dispersion and randomness of concrete cracking under compressive loads make it challenging to predict the diffusion rate of chloride ions. In this paper, the cohesive element method was employed to quantitatively calculate and determine the form and width of dispersed cracks in concrete. These results were found to be consistent with the real concrete crack forms obtained using digital image correlation (DIC) technology. The findings indicate that both the form and width of the cracks significantly impact the diffusion of chloride ions within the concrete. Chloride ion diffusion is enhanced when the cracks are closer to the penetration side or when there are more cracks present in the concrete. Additionally, an increase in axial load amplifies the randomness of chloride ion distribution at the same penetration depth. While coarse aggregates can impede chloride ion penetration, wider cracks lead to a higher concentration of chloride ions within the concrete. Our results contribute to a deeper understanding of chloride ion diffusion in cracked concrete under varying stress levels.

Leakage Quantification in Metallic Pipes under Different Corrosion Exposure Times

The combined effects of aqueous corrosion, stress factors, and seeded cracks on leakage in cast iron pipes have not been thoroughly examined due to the complexity and difficulty in predicting their interactions. This study seeks to address this gap by investigating the interdependencies between corrosion, stress, and cracks in cast iron pipes to optimise the material selection and design in corrosive environments. Leakage experiments were conducted under simulated localised corrosive conditions and internal pressure, revealing that leakage increased from 0 to 25 mL with crack sizes of 0.5 mm, 0.8 mm, 1 mm, and 1.2 mm, along with corrosion times of 0, 120, 160, and 200 h, and varying stress levels. An empirical model was developed using a curve-fitting approach to map the relationships among corrosion time, crack propagation, and leakage amount. The results demonstrate that the interaction between corrosion, stress, and crack propagation was complex and nonlinear, and the leakage amount increased from 0.7 to 0.10 mm every 15 min, as evidenced by SEM microstructure images and empirical data.

Detecting wire breaks in post-tensioned tendons of wind turbines: A signal energy spectrum analysis approach

In the wind industry, recent advancements have led to the research and development of wind turbines featuring hybrid towers, a novel combination of steel tube and precast concrete segments. These concrete modules, which absorb the high stresses caused at the intersection between the tower and its foundation, are commonly joined with post-tensioned tendons. This study focuses on the identification of wire breaks in post-tensioned tendons through the application of acoustic emission testing. Measurements involve the evaluation of wire breaks under controlled laboratory conditions and the analysis of the dynamic operational environment of a functioning wind turbine. The investigation encompasses the development and assessment of a methodology based on principles of discrete Fourier transformation and Parseval’s theorem for analyzing the frequency-dependent energy distribution of acoustic signals. This analytical approach extends to the examination of wire breaks generated under varying stress levels as well as the operational noise within the actual wind turbine. The findings demonstrate a notable concentration of energy within the frequency range of 5-20 kHz in the wire break signals. In contrast, the operational noise signals show a distinct pattern, presenting an extreme value distribution within the 0-2 kHz range. The developed methodology exhibits robustness, even in the presence of high background noise levels, establishing itself as a valuable tool for wire break detection. Additionally, its potential for integration with machine learning algorithms offers the prospect of automated wire break detection, enabling further advancements in structural health monitoring for wind turbines.

Structural behavior and mechanical fatigue of plate and shell heat exchangers through finite element analysis

Plate and Shell Heat Exchangers (PSHE) are vital in industries due to their adaptability and efficiency. This study applied the finite element method to analyze PSHE plate behavior, which is challenging to assess experimentally. The equivalent von Mises stress field was determined for four-plate setups under different conditions: internal channel pressure, external channel pressure, and pressure in both branches. Peak stresses were found at corrugation tops during contact, varying stress levels based on operating conditions. Stresses decreased when both branches were pressurized but increased with single-branch pressurization. Internal and external pressure-only scenarios had distinct stress patterns. The chevron angle and corrugation contact points influenced plate stiffness and stress distribution. A fatigue analysis assessed plate lifespan under cyclic loads, with fatigue strength reduction factors applied according to Soderberg, Goodman, and Gerber failure criteria. This comprehensive analysis provides critical insights into PSHE plate performance, aiding in their reliable application in the industry. All numerical data obtained in this work were validated based on experimental studies previously published in the literature for stress and fatigue analysis.

Experimental Analysis of Resilient Characteristics of CRMB – 55 & 60 Grade with Grade-II Aggregates on Pavement

An evaluation of the physical and engineering properties of modified binders was conducted in this paper, namely Crumb Rubber Modified Bitumen (CRMB - 55 grade & CRMB - 60 grade) containing cement as a mineral filler of 2 % and varying binder contents between 4% and 6% for determining the Optimum Binder Content (OBC) for aggregates of nominal size 13.2 mm in Grade-II. As a result of varying stress levels from 10% to 40%, the specimens have been cast for indirect tensile strength (ITS), moisture susceptibility, and fatigue cycles’ estimation. Keywords: Stability, Modified binder, In-direct tensile strength, fatigue cycle of modified binders.

Static and dynamic strength properties of highly structured clay-rich diatomite in Shengzhou, China

Diatomite is a widespread geological substance found in coastal and lake areas worldwide. Although diatomites are increasingly used in geotechnical engineering construction, a significant knowledge gap exists regarding their mechanical responses to static and dynamic loadings, particularly in high-speed railway projects. This study investigates the static and dynamic behaviors of diatomites through extensive experiments, considering both natural and remolded states. It focuses on representative diatomite specimens obtained from the Shengzhou region in China, an area intersected by the Hang-Shao-Tai high-speed railway. The results of uniaxial compression and undrained triaxial shear tests show that the structural degradation of diatomite significantly impacts its stress-strain responses, failure patterns, and mechanical parameters under static and dynamic loading conditions. The structural effects of natural diatomite tend to degrade as the confining pressure level increases, resulting in corresponding changes in its mechanical parameters. Undrained triaxial shear tests conducted on natural diatomite reveal that the inclinations of the shear band closely correspond to those predicted by the Mohr-Coulomb solution. Additionally, we present a modified hyperbolic-type model to evaluate the damping ratio of diatomites. Furthermore, a power-law model based on Hardin's formula was used to predict the maximum shear modulus of diatomites under varying stress levels and void ratios. Microstructural and chemical analyses were conducted using scanning electron microscopy and X-ray diffraction to gain insights into the observed structural effects at the microscale.

Investigating stress-induced effects on the multifaceted properties of cubic NaTaO3 perovskite oxide: prospects for advanced applications

This study explored the structural, optoelectronic, elastic, mechanical, and thermodynamic behaviour of NaTaO3 cubic perovskite oxide, under varying stress levels. Geometric property analysis reveals a decrease in lattice constants from 4.1 Å to 3.7 Å and cell volume from 71.1–53.4 Å3 as stress increases from 0 to 100 GPa. X-ray diffraction analysis indicated the stable cubic phase with slight peak shifts, demonstrating the material's structural flexibility. Electronic properties revealed an initial increase in the band gap (1.698 eV to 1.936 eV) with applied stress up to 60 GPa, which could be attributed to complex interactions within the material's electronic structure. Optical property analysis suggested that NaTaO3 possessed high optical absorption and conductivity, along with low reflectivity. Furthermore, elastic constants meeting the Born-stability condition (C11 – C12 > 0, C11 + 2C12 > 0, and C44 > 0) confirm the material's mechanical stability. Additional characteristics like the Poisson ratio, Cauchy pressure, and Frantsevich ratio highlighted the ductile and anisotropic nature of NaTaO3. Thermodynamic and phonon dispersion analysis suggested that NaTaO3 can withstand high-stress levels, evidenced by its elevated Debye temperature, indicating superior mechanical stability and increased resistance to thermal degradation. Based on these findings, NaTaO3 proposed as a potential candidate for photovoltaic and thermoelectric devices.

Morpho-physiological adaptations to drought stress in nitrogen-fixing and non-nitrogen-fixing plants

Drought profoundly affects the morpho-physiological responses of desert plants in dryland. To scrutinize the morpho-physiological responses of nitrogen (N)-fixing legumes (Ammopiptanthus mongolicus, Caragana korshinskii), N-fixing non-legumes (Elaeagnus angustifolia, Hippophae rhamnoides), and non-N-fixing plants (Nitraria tangutorum, Haloxylon ammodendron) under varied drought stress levels (75%, 50%, 25% and 5% of soil water holding capacity), a pot experiment was conducted in greenhouse. Following prolonged water deficit, carbon (C) and N stoichiometry, metabolic rates, plant growth, and biomass distribution of unstressed and stressed plants were recorded. Intensified drought significantly reduced stem, root and whole-plant biomass, with no significant changes observed in leaf dry-fresh mass ratio, specific leaf area, intrinsic water use efficiency and root to shoot ratio. However, other traits were impacted differently, reflecting distinct adaptive strategies to drought among three plant functional types (PFTs). Patterns of trait-soil water content (SWC) relationships varied across different PFTs, with N-fixing non-legumes followed by N-fixing legumes displayed greater sensitivity to SWC variations than non-N-fixing plants. This resulted in a shift from a stronger trait-SWC relationship in N-fixing non-legumes and N-fixing legumes to a less correlated relationship in non-N-fixing plants. The diverse responses to drought among PFTs suggest a shift from N limitation to water limitation as SWC decreases.

Novel supramolecular luminescent metallogels containing Tb(iii) and Eu(iii) ions with benzene-1,3,5-tricarboxylic acid gelator: advancing semiconductor applications in microelectronic devices.

A novel strategy was employed to create supramolecular metallogels incorporating Tb(iii) and Eu(iii) ions using benzene-1,3,5-tricarboxylic acid (TA) as a gelator in N,N-dimethylformamide (DMF). Rheological analysis demonstrated their mechanical robustness under varying stress levels and angular frequencies. FESEM imaging revealed a flake-like hierarchical network for Tb-TA and a rod-shaped architecture for Eu-TA. EDX analysis confirmed essential chemical constituents within the metallogels. FT-IR, PXRD, Raman spectroscopy, and thermogravimetric analysis assessed their gelation process and material properties, showing semiconducting characteristics, validated by optical band-gap measurements. Metal-semiconductor junction-based devices integrating Al metal with Tb(iii)- and Eu(iii)-metallogels exhibited non-linear charge transport akin to a Schottky diode, indicating potential for advanced electronic device development. Direct utilization of benzene-1,3,5-tricarboxylic acid and Tb(iii)/Eu(iii) sources underscores their suitability as semiconducting materials for device fabrication. This study explores the versatile applications of Tb-TA and Eu-TA metallogels, offering insights for material science researchers.

ATF4 in cellular stress, ferroptosis, and cancer.

Activating transcription factor 4 (ATF4), a member of the ATF/cAMP response element-binding (CREB) family, plays a critical role as a stress-induced transcription factor. It orchestrates cellular responses, particularly in the management of endoplasmic reticulum stress, amino acid deprivation, and oxidative challenges. ATF4's primary function lies in regulating gene expression to ensure cell survival during stressful conditions. However, when considering its involvement in ferroptosis, characterized by severe lipid peroxidation and pronounced endoplasmic reticulum stress, the ATF4 pathway can either inhibit or promote ferroptosis. This intricate relationship underscores the complexity of cellular responses to varying stress levels. Understanding the connections between ATF4, ferroptosis, and endoplasmic reticulum stress holds promise for innovative cancer therapies, especially in addressing apoptosis-resistant cells. In this review, we provide an overview of ATF4, including its structure, modifications, and functions, and delve into its dual role in both ferroptosis and cancer.

Hybrid machine learning model and predictive equations for compressive stress-strain constitutive modelling of confined ultra-high-performance concrete (UHPC) with normal-strength steel and high-strength steel spirals

Stress-strain constitutive model for confined ultra-high-performance concrete (UHPC) plays a pivotal role in the design and modelling of UHPC structures. However, while extensive research exists on the stress-strain responses of unconfined UHPC, a notable dearth of studies focuses on the stress-strain constitutive model for confined UHPC. Accordingly, this study introduces a novel hybrid machine learning (ML)-based stress-strain constitutive model for UHPC confined with normal-strength steel (NSS) or high-strength steel (HSS) spirals. Given the limited experimental data available, a numerical model was developed and validated against experimental results of confined UHPC. Subsequently, it was employed to generate a comprehensive dataset of confined UHPC stress-strain responses, which were then used to train the hybrid ML model. Hyperparameters of the model are subsequently optimized using Optuna along with a cross-validation technique. The optimized hybrid ML model exhibited exceptional accuracy in predicting the stress-strain response of confined UHPC with NSS or HSS spirals, as demonstrated by high coefficients of determination (R2) values ranging from 0.905 to 0.999 and low error metrics across varying stress levels and datasets. Moreover, the capability of the model to simultaneously predict both stress and strain responses was further validated through canonical correlation analysis (CCA). The results of the analysis demonstrated robust predictive performance of the model, with high CCA scores that ranged between 93.3% and 99.4%. To facilitate the practical implementation of the model, an end-to-end interactive software tool is developed. In addition, this study proposes predictive equations for the peak and ultimate stress-strain responses of confined UHPC. The evaluation of the developed predictive equations demonstrates their efficacy in accurately predicting the stress-strain responses of confined UHPC, as evidenced by the high R2 values, which ranged from 83–91%.

Perceived stress and anxiety among medical students at Helwan University: A cross-sectional study.

Medical students are prone to high levels of perceived stress and anxiety, which can negatively impact their academic performance, as well as their physical and mental health. This study aimed to assess the main stressors, levels of perceived stress and anxiety, and their predictors among medical students. A structured questionnaire was used to collect data from 1696 medical students at Helwan University. A cross-sectional study was designed to evaluate their perceived stress, stressors, and anxiety using the Perceived Stress Scale, Medical Students Stressor Questionnaire, and Beck Anxiety Inventory, respectively. Approximately 93% of medical students experienced moderate to high levels of stress, while 54.9% of medical students experienced moderate to concerning levels of anxiety. The main stressors were academic, teaching, social, intrapersonal, group activity, and desire-related stressors. Risk factors associated with higher perceived stress included being female, young age, living away from the family, obtaining lower academic percentages, having psychiatric, neurological, or other chronic medical illnesses, and experiencing higher levels of academic, intrapersonal, drive, and group activities-related stressors. Risk factors for higher anxiety included being female, residing in rural areas, having psychiatric, neurological, or other chronic medical illnesses, perceiving a high level of stress, and experiencing higher levels of academic, intrapersonal, and social-related stressors. The findings indicate that a significant proportion of medical students experience various levels of stress and anxiety. These results underscore the urgent need for a stress management program, to help medical students to cope with different stressors.