Search Results (32)

In this study, with the rapid development of the field of rail vehicles, the laser welding process with high energy and small thermal deformation is selected, which reduces the working hours of post-welding grinding, repainting, and other processes, and ensures the industrial design requirements of the beautiful body after welding. The welding process for the non-penetration laser lap welding of SUS301L stainless-steel plates was optimized to address the problem of welding marks on the outer surface of railway vehicle car bodies. The impact of laser power, welding speed, and defocusing amount on weld penetration and tensile shear load was investigated using the response surface methodology. The results showed that the optimal response model for tensile shear load was the linear model, while the optimal response model for weld penetration was the 2FI model. The defocusing amount had the greatest influence on tensile shear load and weld penetration. When the laser power was 1.44 kW, the welding speed was 15 mm/s, and the defocusing amount was −4 mm, the tensile shear load reached its maximum by prediction. The actual tensile shear load of welded joints using these parameters was 4293 N with an error of merely 0.31% relative to the predicted value. The shear strength of laser-welded joints was measured at 429.3 N/mm, meeting the criteria established by the relevant standards. The tensile fracture shows characteristics of brittle fracture. The surface of the welded joints was bright white and well-formed, while the back side of the lower plate exhibited no signs of melting or welding marks. The microstructure of the weld zone (WZ) exhibited irregular columnar austenite and plate-like ferrite, while the heat-affected zone (HAZ) comprised columnar austenite and elongated bars or networks of δ-ferrite. The small-angle grain in welded joints can reduce grain boundary defects and mitigate stress concentration. After welding, angular deformation occurred, resulting in a residual stress distribution that shows tensile stress near the weld and compressive stress at a distance from the weld. Full article

Truck drivers experience an elevated risk of being involved in a fatigue-related crash or incident. In Australia, approximately one third of fatal truck crashes are fatigue-related. Various contextual factors are known to increase truck crash risk, including long working hours, irregular schedules, delays while loading and unloading and limited access to suitable rest areas. Studies investigating personal factors affecting Australian truck drivers’ attitudes and compliance with fatigue-management requirements, however, are lacking. Semi-structured interviews were conducted with Australian truck drivers and transport managers (N = 44) to determine how personal and contextual factors influence their intention to comply with fatigue regulation. The findings indicate that personal factors such as familial pressure, financial viability as well as inflexible enforcement and its personal consequences may influence fatigue-related health risks and compliance behaviours. This includes contextual factors such as work scheduling, training and new risk monitoring technologies. It is argued that government, transport industry peak bodies, managers, unions and truck drivers should work together to co-develop fatigue management strategies that account for personal factors likely to influence truck drivers’ intentions regarding fatigue compliance. This will support them to engage in safer and healthier fatigue management practices. Full article

Predicting the behavior of Internet of Things (IoT) networks under irregular topologies and heterogeneous battery conditions remains a significant challenge. Simulation tools can capture these effects but can require high manual effort and computational capacity, motivating the use of machine learning surrogates. This work introduces an automated pipeline for generating large-scale IoT network datasets by bringing together the Contiki-NG firmware, parameterized topology generation, and Slurm-based orchestration of Cooja simulations. The system supports a variety of network structures, scalable node counts, randomized battery allocations, and routing protocols to reproduce diverse failure modes. As a case study, we conduct over 10,000 Cooja simulations with 15–75 battery-powered motes arranged in sparse grid topologies and operating the RPL routing protocol, consuming 1300 CPU-hours in total. The simulations capture realistic failure modes, including unjoined nodes despite physical connectivity and cascading disconnects caused by battery depletion. The resulting graph-structured datasets are used for two prediction tasks: (1) estimating the last successful message delivery time for each node and (2) predicting network-wide spatial coverage. Graph neural network models trained on these datasets outperform baseline regression models and topology-aware heuristics while evaluating substantially faster than full simulations. The proposed framework provides a reproducible foundation for data-driven analysis of energy-limited IoT networks. Full article

Undergraduate students and healthcare professionals often experience irregular sleep patterns, social jet lag (SJL), and rotating shifts that affect their performance. This study examined the association between SJL, sleep duration, and psychosocial factors among 1409 Colombian undergraduate students (mean age 24.4 ± 6.7 years) using data from the Ultra-Short Version of the Munich ChronoType Questionnaire collected between June and September 2023. Multivariable linear regression analysis identified factors associated with SJL. The prevalence of SJL exceeding two hours was high (84.6%), with an average magnitude of 4.4 h. Chronotype (MSFsc) was negatively correlated with SJL, indicating that students with later chronotypes tended to experience greater misalignment between biological and social time. Younger age and a higher number of working days were significantly associated with increased SJL, whereas substance use and mental health history showed no significant effects. These findings highlight that work-related demands, particularly frequent working days, play a key role in exacerbating social jet lag. The results underscore the need for institutional strategies to promote sleep health among Colombian university students and health professionals. Full article

Background: Shift work necessitates alterations in daily routines, which can be detrimental to workers’ health and may also influence the activity and rest patterns of their children. Aim: The aim of this study was to evaluate the concordance between activity and rest parameters of mothers and their children, according to the mothers’ work shift (day vs. night). Methods: Twelve mother–child dyads participated in this study, including six mothers working night shifts and six working day shifts. All mothers followed a 12/36 h rotating schedule (07:00–19:00 for day shifts; 19:00–07:00 for night shifts). Participants wore actigraphy devices for 10 consecutive days. Sleep and motor activity parameters were analyzed using the Bland–Altman method. Results: Analysis of the five least active hours (L5) revealed increased nocturnal activity among the night shift group. The period of the 10 most active hours (M10) suggested greater activity in the day shift group, with a smaller difference between mother and child in the day shift group. The relative amplitude (RA) in the night shift group was lower among mothers compared to the day group. Interdaily stability (IS) was lower, and intradaily variability (IV) was higher in the night shift group, suggesting more irregular activity patterns. Bedtime data showed greater variability in the night shift group, with night shift mothers typically going to bed later than their children—a pattern that was also observed for wake times. In the day shift group, total sleep time did not differ between mothers and children; however, in the night shift group, discrepancies increased proportionally with total sleep duration. Sleep efficiency was lower among mothers in both groups, but the difference between mother and child was more pronounced in the night shift group. Conclusions: Night shift work among mothers appears to negatively affect both their own and their children’s activity and sleep parameters when compared to those in the day shift group. Full article

Shift workers are commonly associated with circadian misalignment due to irregular working hours, which often leads to poor sleep quality and is associated with HPA axis misalignment and changes in cardiovascular outcome. Background: This systematic review aimed to investigate the association between cortisol production and cardiovascular health with sleep quality in healthcare shift workers. Methods: A comprehensive search of PubMed, Web of Science, and Scopus was conducted for studies published between 2010 and 2025, according to PRISMA guidelines. Fourteen studies met the inclusion criteria. Results: Among the included studies, eight studies focused on the relationship between sleep quality and cortisol regulation, five studies investigated the link between sleep quality and cardiovascular health, and one study examined sleep quality, cortisol regulation, and cardiovascular outcome. A significant relationship between cortisol and sleep quality was observed, as lower cortisol levels upon awakening were associated with low sleep quality. Several studies reported that sleep disturbances were associated with adverse cardiovascular outcomes, including reduced heart rate variability (HRV) and increased risk of metabolic syndrome. Conclusions: This review highlights existing literature on the critical role of sleep quality as a key factor in cortisol level and cardiovascular health in shift workers, along with the factors influencing circadian rhythm. Full article

Background/Objectives: Seafarers are a particularly isolated workforce, as they are on-site only with their colleagues, both on and off duty. Long-term duties in the sea environment, irregular working hours, changing time zones, and lack of sleep are some of the many factors that negatively affect the physical and mental health of seafarers. This study aimed to explore the occupational stressors faced by seafarers in Lithuania using the HSE Management Standards Indicator Tool (HSE-MSIT). Methods: In 2023, a quantitative study, using a paper survey, of seafarers’ occupational stressors was conducted in Klaipeda city, Lithuania. A total of 385 Lithuanian seafarers participated in the study. Results: The greatest sources of stress at work were identified as changes at work, relationships, peer support, and management support. Role clarity, demands, and work control were not strong stressors for the seafarers. Analysis of perceived stress levels revealed notable differences between groups with different work experience and job positions. Analysis of years of service (0–11 years vs. 12+ years) found that seafarers with shorter service experienced more stress in terms of demands (p = 0.005), role clarity (p = 0.004), work control (p = 0.035), and relationships (p = 0.02). Based on job position (senior vs. junior), junior seafarers experienced significantly higher stress in the demands (p = 0.001) and role clarity (p = 0.009) subscales. The study revealed that job position and years of work had weak negative correlations with stress indicators at work. The Demands subscale was moderately positively correlated with relationships and change at work. The Relationships subscale was moderately positively correlated with peer support and change at work. Role clarity was moderately negatively correlated with change at work and relationships. Conclusions: Overall, changes at work, relationships, peer support, and management support in the working environment emerged as key factors of perceived stress among seafarers. Junior seafarers and seafarers with shorter years of service experienced higher stress at work. These findings may help in the development of targeted stress management and training strategies tailored to different profiles of seafarers. Full article

Background/Objectives: Obesity is an emerging public health problem in the world, and health professionals are most likely to be exposed to several occupational determinants thereof. These include long working hours, shift work, high job stress, irregular food intake, poor opportunities for healthy eating, and physical inactivity at work. Healthcare workers’ stressful jobs typically lead to poor eating habits and less opportunity for physical exercise, contributing to obesity risk. The primary objective of this study is to determine the prevalence of obesity among healthcare employees and identify unique predictors that contribute to obesity in this population. Material and Methods: Data were collected between 2021 and 2023 from 557 participants through anthropometric measurement and a structured questionnaire using a stratified random sampling technique. Results: The study found that 18.6% of participants were classified as obese or morbidly obese (12.9% and 5.7%, respectively), while 33.8% were overweight. The strong predictors of obesity included older age (>30 years, AOR = 2.404, p < 0.001) and working in nursing services (AOR = 1.999, p = 0.003). Furthermore, 34.3% of respondents had no physical activity, 71.5% slept less than 8 h per day, and 58.5% consumed fast food one to two times per week. A significant association of obesity was found with gender (p < 0.001), females being at higher risk, and type of department (p = 0.002), nursing staff being at higher risk. However, the predictable factors for obesity did not include nationality, family size, hours of TV watching, and fast-food consumption. Conclusions: These findings highlight a significant burden of obesity among healthcare employees, underscoring the need for workplace interventions. The strategy to address obesity among this highly vulnerable population should be directed toward enhancing physical activities, improving eating habits, and managing occupational stress, particularly for older workers and nursing staff. Full article

Background: In today’s fast-paced work environment, work engagement is crucial for both organizational success and individual well-being. Objective: Our aim is this study was to analyze the associated factors of work engagement, work overload, work satisfaction, and emotional exhaustion and describe their effect on nurses and physicians in the Central Catalonia Health Region during 2023. Methods: A multicenter cross-sectional study was conducted using an online questionnaire at the Territorial Management of Central Catalonia (Spain). The questionnaire was accessible from 28 November 2022 to 12 March 2023. The analysis was performed using the SPSS software. CHERRIES (Checklist for Reporting Results of Internet E-Surveys) guidelines were followed for communicating research results. Results: A total of 321 professionals answered the questionnaire, 60.7% of whom were nursing professionals and 39.3% of whom were medical professionals. Work overload, work satisfaction, and emotional exhaustion were associated with work engagement. Being a physician, permanent contracts, irregular work shifts, overtime, and salary were related to work overload and emotional exhaustion. Being a woman, salary, academic level, and irregular work shifts were related to work satisfaction. There was a gender inequality in work engagement among nursing professionals to the detriment of men. In terms of class inequality, there was a difference between occupational groups with respect to work overload and emotional exhaustion among women. Conclusions: Organizational practices need to be improved to promote greater engagement and work satisfaction, as well as to reduce emotional overload and exhaustion. This may include regulating unpaid overtime and promoting more stable working hours. Full article

Background/Objectives: Health management in workers in the taxi industry is particularly challenging due to irregular working hours and the need to prevent fatal accidents. In addition, drivers in Japan are aging, and the early prevention of age-related deterioration in oral health is an increasingly important issue. The aim of this cross-sectional study was to investigate the relationships between oral diadochokinesis (OD), tongue pressure, and lip-seal strength in Japanese male taxi workers. Methods: Measurements of tongue pressure and lip-seal strength were performed by dentists using specialized equipment. OD was measured using the number of consecutive “Pa”, “Ta”, and “Ka” vocalizations that could be produced in 5 s. We performed multiple regression analysis to examine the effects of lip-seal strength and tongue pressure on OD. Results: The study included 437 participants, excluding 17 who could not complete all oral cavity measurements. Tongue pressure showed a significant positive correlation with “Pa”, “Ta”, and “Ka” (correlation coefficients: 0.527–0.680). Lip-seal strength was not significantly correlated with OD. Tongue pressure showed a significant positive correlation with “Pa”, “Ta”, and “Ka”. In the results of multiple regression analyses without the elderly participants, tongue pressure was associated with “Pa” (β[95% confidence interval]: 0.574[0.304, 0.843]), “Ta” (0.436[0.231, 0.640]), and “Ka” (0.424[0.210, 0.639]), and lip-seal strength was associated with “Pa” (0.128[0.032, 0.224]) and “Ka” (0.083[0.006, 0.160]). Conclusions: OD may be associated with lip-seal strength and tongue pressure even without including elderly workers. Regardless of age, maintaining good OD may help maintain lip-seal strength and tongue pressure, which may play a role in reducing the risk of age-related oral disorders. Full article

Musculoskeletal disorders occur frequently in industrial settings, and police officers in particular are at high risk of developing musculoskeletal disorders due to the nature of their work, but research on this is lacking. Therefore, the purpose of this study was to examine the prevalence and risk factors of musculoskeletal disorders according to the job functions of police officers. A survey was conducted, targeting active-duty police officers, and data were collected from 4268 respondents who answered all items on the questionnaire. As a control group, we used the general population dataset from the 2020 National Health and Nutrition Examination Survey conducted in Korea. The survey included general information such as gender, age, working hours, and type of work. It also investigated medical utilization, including the frequency of medical visits and hospitalizations. The assessment of musculoskeletal disorders was analyzed using pain NRS, VAS, SPADI, and ODI. The working characteristics of police officers were found to be more irregular in terms of working hours and involved a higher intensity of work activities compared with the general population. However, there was a lack of precise diagnoses and continuous treatment for these disorders. These results imply that police officers’ occupational characteristics are related to musculoskeletal disorders. Considering the direct relationship between police officers’ health and public safety, systematic evaluation and management of their musculoskeletal disorders are needed. Full article

This work investigates the ionospheric response to the March 2023 geomagnetic storm over American and Asian sectors from total electron content (TEC), rate of TEC index, ionospheric heights, Swarm plasma density, radio occultation profiles of Formosat-7/Cosmic-2 (F7/C2), Fabry-Perot interferometer driven neutral winds, and E region electric field. During the storm’s main phase, post-sunset equatorial plasma bubbles (EPBs) extend to higher latitudes in the western American longitudes, showing significant longitudinal differences in the American sector. Over the Indian longitudes, suppression of post-sunset irregularities is observed, attributed to the westward prompt penetration electric field (PPEF). At the early recovery phase, the presence of post-midnight/near-sunrise EPBs till post-sunrise hours in the American sector is associated with the disturbance of dynamo-electric fields (DDEF). Additionally, a strong consistency between F7/C2 derived amplitude scintillation (S4) ≥ 0.5 and EPB occurrences is observed. Furthermore, a strong eastward electric field induced an increase in daytime TEC beyond the equatorial ionization anomaly crest in the American region, which occurred during the storm’s main phase. Both the Asian and American sectors exhibit negative ionospheric storms and inhibition of ionospheric irregularities at the recovery phase, which is dominated by the disturbance dynamo effect due to equatorward neutral winds. A slight increase in TEC in the Asian sector during the recovery phase could be explained by the combined effect of DDEF and thermospheric composition change. Overall, storm-time ionospheric variations are controlled by the combined effects of PPEF and DDEF. This study may further contribute to understanding the ionospheric responses under the influence of storm-phase and LT-dependent electric fields. Full article

In recent years, the demand for efficient and sustainable agricultural practices has been leveraged, leading to smart farming practices. These practices aim to enhance agricultural processes and productivity and minimize resource waste. One of the crucial challenges faced by farmers is the uneven distribution of soil humidity and pH across their agricultural lands. Further, the irregularity in soil moisture content and pH can lead to poor crop performance, water wastage, and increased resource utilization. In this work, an Internet of Things-based smart sensor node was developed, which consists of humidity and pH sensors to ensure the efficient management of water and soil conditions across an entire farm. Also, an array of humidity and pH sensors were placed across the farm, and these units worked independently as they have their own controller and battery unit. The developed device was integrated with a solar cell, which charged the battery. Further, the data acquired from these sensors were wirelessly transmitted to the base station, and it gathered the information of each unit, including their humidity levels, pH values, signal strength, and energy supply. This information was processed at the base station, and a graphical overview of the farm with the acquired information was represented, which provides farmers with real-view insight to identify areas with poor humidity and pH conditions. These data were transmitted to an IoT cloud, offering the farmer the ability to monitor their farm from a remote location. In cases where humidity levels dropped drastically and remained unchecked for more than two hours, the system triggered an alert. This mechanism makes sure that farmers are notified of potential issues, allowing them to prevent crop damage and optimize their resource usage. Full article

The management of nutrition, food, and health for disaster relief personnel is one of the crucial aspects for carrying out effective rescue activities during large-scale natural disasters, such as a big earthquake, flooding, and landslide following heavy rainfall or man-made disasters, such as widespread fire in industrial areas. Rescue workers, such as fire fighters and rescue teams who work on the disaster relief operations, have to work long, hard, and irregular hours that require energy (both intake and expenditure), with especially altered eating patterns. Reliable estimates of the energy expenditure (TEE) for such disaster relief operations have not been fully established. Here, we propose to clarify the energy expenditure for each type of large-scale disaster activity conducted by fire fighters. Thirty fire fighters (survey participants in this research) who participated in the simulation training of large-scale disaster activities wore tri-axial accelerometers and heart rate monitors during training; and, post-training, 28 fire fighters submitted complete activity record tables. An estimation formula combining tri-axial accelerometer and heart rate monitor data was used. Additionally, energy expenditure per hour (excluding resting energy expenditure: REE) (per average body weight of participants) was calculated for 10 types of large-scale disaster response activities. We propose utilization of these data as a reference value for examining the TEE of firefighting and rescue operations in future large-scale disasters. Full article

Construction laborers are constantly subjected to irregular work hours, leading to insomnia and poor sleep quality, which impacts cognitive and rational behavior. This negatively influences decision-making capabilities, resulting in accidents on site. This study determined the effect of sleep quality on the cognitive behavior and rational ability of construction laborers. A quantitative research design comprised of a questionnaire survey was conducted for data collection purposes. Respondents comprised a randomly selected sample of construction workers, and a statistical analysis of the results was performed to investigate existing correlations. Data were collected using questionnaires from 575 and 310 respondents in the initial and latter phases, respectively, from five construction companies in Southern India, and analyzed using inferential statistics. Shift work negatively affects both the early and late phases of rational abilities. A negative correlation was observed between age and disturbed rationality in the late phase, despite not being observed in the early phase. Gender, rational ability, age, shift work, sleep quality, and cognitive behavior were not correlated in either the early or late phases. Furthermore, age, shift work, and sleep quality were not correlated with cognitive behavior. Rather, sleep quality and shift schedules were associated with rational ability and cognitive behavior impairment. There was a transient relationship between insufficient sleep and the ability to make rational decisions. This study contributes to the current discourse regarding the improvement of the sleep health of construction workers to enhance their well-being and productivity. Full article