Search Results (3,570)

Film cooling has been increasingly applied in turbine blade cooling design due to its excellent cooling performance. Although film-cooled blades demonstrate superior cooling effectiveness, the perforation design on blade surfaces compromises structural integrity, making fatigue failure prone to occur at cooling holes. Previous studies by domestic and international scholars have extensively investigated factors influencing film cooling effectiveness, including blowing ratio and hole geometry configurations. However, most research has overlooked the investigation of fatigue life in film-cooled blades. This paper systematically investigates blade fatigue life under various cooling air parameters by analyzing the relationships among cooling effectiveness, stress distribution, and fatigue life. Results indicate that maximum stress concentrations occur at cooling hole locations and near the blade root at trailing edge regions. While cooling holes effectively reduce blade surface temperature, they simultaneously create stress concentration zones around the apertures. Both excessive and insufficient cooling air pressure and temperature reduce thermal fatigue life, with optimal parameters identified as 600 K cooling temperature and 0.75 MPa pressure, achieving a maximum thermal fatigue life of 3400 cycles for this blade configuration. A thermal shock test platform was established to conduct fatigue experiments under selected cooling conditions. Initial fatigue damage traces emerged at cooling holes after 1000 cycles, with progressive damage expansion observed. By 3000 cycles, cooling holes near blade tip regions exhibited the most severe failure, demonstrating near-complete functional degradation. These findings provide critical references for cooling parameter selection in practical aeroengine applications of film-cooled blades. Full article

Symmetrical bearing raceway led to the axial sliding of rolling elements, which is a crucial factor in shortening the operational lifespan. This study addresses this limitation through three-step advancements: first, a parametric equation for logarithmic spiral raceways is developed by analyzing their asymmetric geometric features; second, based on the geometrical model, we systematically investigate the parameters of the logarithmic spiral that affects the bearing performance metrics; and finally, a novel fatigue life prediction framework that integrates static mechanical analysis with raceway parameters establishes the theoretical foundation for optimizing the raceway parameters. The results of the model analysis show that the error of the maximum contact stress verified by the finite element method is less than 8.3%, which verifies the model’s accuracy. Increasing the contact angle α of the outer ring from 82 to 85 can increase fatigue life by 15.6 times while increasing the initial polar radius O of the inner ring from 7.8 mm to 8.1 mm will cause fatigue life to drop by 86.9%. The orthogonal experiment shows that the contact angle α of the outer ring has the most significant influence on the service life, and the optimal parameter combination (clearance δ of 0.02 mm, inner race and outer race strike angles α of 85°, an inner race initial polar radius $r_o$ of 7.8 mm, and an outer race initial polar radius $r_o$ of 7.9 mm) achieves a 60.7% fatigue life increase. The findings provide theoretical support and parameter guidance for the optimal bearing design with logarithmic spiral raceways. Full article

Background and Objective: Fatigue represents a hallmark symptom in Multiple Sclerosis (MS), but its diagnosis and clinical evaluation is difficult because it is described as a subjective feeling of exhausted physical and mental sensation. Studies have also shown that approaches based on assisted therapies and robotics, as well as the use of vibration, which are used to improve sensory integration, reduce fatigue. The primary outcome in this study is to evaluate the effects of the application of focal vibrations on the reduction in fatigue, muscle strength, and endurance in MS patients with moderate disability. The secondary outcome is to assess the effects on quality of life, cognitive status, and mood. Methods: We enrolled 40 MS patients. The study was designed as a parallel randomized controlled trial: 20 patients were assigned to the experimental group (EG), who received vibration training, and 20 to the control group (CG), who received traditional physical exercise. Results: We found significant differences in the EG in fatigue, motor, and cognitive outcome and improvement of some aspects of quality of life (QoL). There are correlations between perceived multidimensional fatigue and cadence, step length, and health quality of life composite. Conclusions: Our study demonstrated the potential effectiveness of vibration training in balance, walking endurance, and reduction in the risk of falls in patients with Multiple Sclerosis. In addition, we added evidence about fatigue, non-motor outcomes, in particular promoting mental and physical QoL and individual life satisfaction. The name of the registry is clinicaltrial.gov; the number of registration id NCT05783999; and the date of registration is 14 March 2023. Full article

This study investigates the microstructural evolution and mechanical degradation mechanisms of cold-drawn 310S stainless steel subjected to repeated thermal cycling between 900 °C and room temperature. The results reveal that thermal cycling induces significant lattice distortion, dislocation accumulation, and recrystallization, leading to grain refinement and increased tensile strength. However, these microstructural changes also initiate subsurface cracks and reduce ductility. TGA analysis confirms thermal weight loss from decarburization, especially under oxidative atmospheres. EPMA analysis and tensile tests after thermal cycling reveal that surface cracks formed during thermal cycling act as origins for transgranular crack propagation under tensile stress, significantly reducing fracture resistance. Bending fatigue tests further demonstrate that thermally fatigued specimens exhibit inferior fatigue life compared to raw material, confirming the deteriorating mechanical properties of 310S stainless steel after thermal cycling. Overall, the combined effects of thermal and mechanical fatigue degrade the structural integrity of 310S stainless steel, revealing that lattice distortion and subsurface cracking are the key factors in its embrittlement and reduced fatigue performance. Full article

Oil shale, an unconventional oil and gas resource, can generate the required hydrocarbons through high-temperature pyrolysis. In situ conversion extraction technology utilizes downhole heaters to directly inject high-temperature heat into the oil shale layer to achieve the effect of oil and gas recovery. For the metal material components of the combustion heaters, the uneven temperature fields experienced during the start of operations, processing, and end of operations can lead to fatigue conditions, such as high-temperature creep, micro-damage, and micro-deformation due to thermal effects. To prevent the occurrence of the aforementioned issues, it is necessary to conduct fatigue life analysis of downhole combustion heaters. By combining actual combustion heater operation experiments with finite element simulation, this paper analyzes the impact of temperature, structure, and stress amplitude on the fatigue life of heaters. The results indicate that the fatigue life of the heaters is most significantly influenced by the metal gaskets, and the higher the exhaust gas temperature, the lower the fatigue life of the heater. Heating operations significantly reduce the fatigue life of the heater, while cooling operations have almost no effect on the fatigue life. Circular-pore metal gaskets have a higher fatigue life than those with a square hole shape. Considering only the thickness of the metal gaskets, the thicker the gasket, the higher the fatigue life. Stress amplitude has the most significant impact on the fatigue life of the heater; when the stress amplitude is doubled, the metal gaskets quickly undergo fatigue damage. Full article

Background: Dysarthria is a neuromotor speech disorder that significantly impacts patients’ quality of life. In Chile, there is a lack of culturally validated instruments for assessing dysarthria. This study aimed to cross-culturally adapt the Bogenhausen Dysarthria Scales (BoDyS) into Chilean Spanish and to conduct face and content validation. Methods: The adaptation process included translation and back-translation, followed by validation by a panel of experts. Clarity, format, and length were evaluated, and the Kappa index (KI), content validity index (CVI), and content validity ratio (CVR) were calculated to confirm item relevance. A pilot test was subsequently conducted with ten speech–language pathologists to apply the adapted version to patients. Results: The adaptation process produced a consensus version that preserved the semantic and cultural characteristics of the original scale. The statistical measures (KI = 1.00; I-CVI = 1.00; S-CVI/Ave = 1.00; S-CVI/UA = 1.00; CVR = 1.00) indicated satisfactory levels of agreement. The pilot test demonstrated the scale’s appropriateness and effectiveness for assessing dysarthria within the Chilean context, although some experts recommended reducing task repetition for patients prone to fatigue. Conclusions: The Chilean version of the BoDyS (BoDyS-CL) is a valid and useful tool for evaluating dysarthria in Chile. This study provides a foundation for further research and the systematic implementation of this scale in local clinical practice. Full article

Background: Beach volleyball (BVb) is a highly demanding Olympic sport characterized by intense physical activity and unique environmental challenges, including varying weather conditions and sandy, unstable court surfaces. Despite its popularity, there is a notable lack of scientific research addressing the metabolic and immune responses of elite female athletes in this sport. This study aims to address this gap by investigating two world-class Olympic medalists, female BVb players, who represent a country with a rich history in the sport. Methods: Two athletes underwent a simulated competition day consisting of two matches. A standardized protocol was utilized to collect blood and urine samples at seven time points, allowing for analysis throughout the competition and recovery phases. The analysis included various electrolytes, as well as hematological, metabolic, and inflammatory markers. Additionally, we assessed selected hormones, such as insulin, serotonin, ACTH, and cortisol, along with amino acids related to energy metabolism and neurotransmitter synthesis. Results: Both athletes presented a trend toward electrolyte disturbances, especially hypokalemia, with a mean decrease of 15% and individual values reaching as low as 3.3 mmol/L post-match. This indicates that BVb may pose a risk for such disturbances. Additionally, the matches led to 20% to 60% increases in muscle injury markers, with incomplete recovery even after a day of rest, signaling persistent physiological stress post-competition. This increase was matched by stimulating stress hormones (ACTH and cortisol rose up to 4-fold and 3-fold, respectively), and markers of exercise intensity, such as lactate and ammonium. Moreover, the simulated BVb competition day impacted the amino acid response, with the Fischer ratio (BCAA/AAA) and blood tryptophan decreasing to a minimum of 60% of the initial levels and blood serotonin increasing by up to 180%, which are signs of an increased risk of central fatigue onset, according to the Fischer and Newsholme theory. Conclusions: The responses examined in this exploratory study contribute to a deeper understanding of the metabolic and immune demands placed on elite female BVb players, suggesting practical applications. By addressing the similar physiological responses observed among the athletes and emphasizing their unique individual responses—despite following the same protocol under identical conditions and sharing similar life habits for an extended period—this study highlights the critical necessity for the n-of-1 monitoring of athletes. Full article

Background/Objectives: Hepatocellular carcinoma (HCC) is a major cause of cancer-related mortality worldwide, with transarterial chemoembolization (TACE) commonly used as a palliative approach for patients who are not candidates for surgical resection. Understanding the factors that influence health-related quality of life (HRQoL) after TACE is essential for improving patient-centered care. This systematic review seeks to consolidate current evidence on the variables that impact HRQoL in HCC patients post-TACE. Methods: In adherence to PRISMA guidelines, a comprehensive search was conducted across five English and Chinese databases—PubMed, Scopus, Web of Science, CNKI, and Wanfang—covering studies from database inception to May 2025. Eligible studies were observational and examined factors affecting HRQoL in post-TACE HCC patients. Two independent reviewers performed screening, data extraction, and quality assessment using the Joanna Briggs Institute (JBI) Critical Appraisal Tools. Results: Nine studies met the inclusion criteria, including six cohort studies and three cross-sectional studies. The quality assessment rated seven studies as high quality and two as moderate. A range of validated HRQoL assessment tools was used, with the EORTC QLQ-C30 and FACT-G being the most commonly employed. The factors influencing HRQoL were grouped into five categories: (1) demographic factors (e.g., age, gender, education level); (2) clinical indicators (e.g., liver function, tumor burden); (3) psychological factors (e.g., depression, anxiety, spiritual well-being); (4) social support (e.g., financial status, coping mechanisms); and (5) physical symptoms (e.g., fatigue, pain, appetite loss). Across studies, both symptom severity and psychological distress were consistently associated with lower HRQoL. Conclusions: The HRQoL of HCC patients following TACE is influenced by a complex interplay of demographic, clinical, psychological, social, and symptomatic factors. Tailored, multidimensional interventions addressing these diverse aspects are crucial to optimizing recovery and improving overall well-being. Full article

In Arctic regions, ship structures face low temperatures, overloads, thickness effects, and fluctuating stress ratios, which significantly influence the fatigue crack growth (FCG) behavior of marine steels. This study investigates the FCG behaviors of DH36 steel by a series of experiments under the combined effects of low temperatures, overload ratios R_ol, specimen thickness B, and stress ratios R. Experiment results show that the yield strength, ultimate tensile strength, and elastic modulus of DH36 steel exhibit negative correlations with temperature varying within the Arctic temperature range. A reduction in fatigue crack growth rate (FCGR) is observed under the combined effects of low temperature and overload, and the magnitude of decrease shows a positive correlation with R_ol. Notably, low temperatures weaken the FCG retardation effect induced by overload, and this attenuation becomes more pronounced as temperature decreases. Under low temperatures, while maintaining constant peak load, increasing R significantly reduces both initial and terminal stress intensity factor ranges ΔK₀ and ΔK_e, resulting in diminished effective crack driving force and thereby substantially extending FCG life. Although increased B enhances FCGR at low temperatures, thinner plates demonstrate shorter FCG life due to their higher ΔK₀ values. Full article

Background/Objective: Stroke is one of the leading causes of death and disability worldwide, with older survivors (aged > 65 years) bearing significant health and economic impacts, particularly in industrialized countries. While gait rehabilitation is a cornerstone in post-stroke recovery and robotic technologies offer promising tools to enhance its effectiveness, the existing literature has largely overlooked elderly populations. Most studies on robot-assisted gait training (RAGT)—which uses exoskeleton or end-effector devices to support and guide movement—either exclude older adults or do not analyze their outcomes separately. This review aims to critically evaluate the current evidence on RAGT in elderly post-stroke patients, addressing a significant gap in the literature and providing novel insights into the effectiveness and adaptability of RAGT for this specific population. Methods: The search included databases such as PubMed, Scopus, Embase, Web of Science, and ClinicalTrials. The inclusion criteria covered studies published up to March 2025, focusing on post-stroke individuals aged >65 years, who underwent RAGT. Results: 25 studies were included in the review, 21 involving exoskeleton and 4 end-effector devices. The primary focus was on motor outcomes, such as gait independence, gait parameters, and balance control. Only a few studies examined non-motor aspects, including cognitive and emotional functions, fatigue, pain, and neuroplasticity. Moreover, data on the long-term effects on the elderly population remain scarce. Conclusions: RAGT is an effective strategy for promoting motor recovery and improving functional outcomes, from independence in daily activities to quality of life, in the post-stroke elderly population. Early and high-intensity interventions are particularly useful with positive effects on neuronal plasticity, cognitive function, and well-being. Full article

This study established a machine learning framework to enhance the accuracy of very-high-cycle fatigue (VHCF) life prediction in selective laser melted Inconel 718 alloy by systematically comparing the use of generative adversarial networks (GANs) and variational auto-encoders (VAEs) for data augmentation. We quantified the influence of critical defect parameters (dimensions and stress amplitudes) extracted from fracture analyses on fatigue life and compared the performance of GANs versus VAEs in generating synthetic training data for three regression models (ANN, Random Forest, and SVR). The experimental fatigue data were augmented using both generative models, followed by hyperparameter optimization and rigorous validation against independent test sets. The results demonstrated that the GAN-generated data significantly improved the prediction metrics, with GAN-enhanced models achieving superior R² scores (0.91–0.97 vs. 0.86 ± 0.87) and lower MAEs (1.13–1.62% vs. 2.00–2.64%) compared to the VAE-based approaches. This work not only establishes GANs as a breakthrough tool for AM fatigue prediction but also provides a transferable methodology for data-driven modeling of defect-dominated failure mechanisms in advanced materials. Full article

Background/Objectives: Although self-compassion practice has been increasingly popular in the literature in recent years, the area of social work knows very little about it. To be self-compassionate is to treat oneself with love and respect. The aim of this study was to investigate the relationship between social workers’ professional quality of life (compassion satisfaction, secondary traumatic stress, and burnout) and self-compassion. Methods: This cross-sectional descriptive study consisted of 177 social workers in primary healthcare (PHC) in Greece. The Self-Compassion Scale (SCS), the Professional Quality of Life Scale (ProQOL-5), and the participants’ personal, demographic, and professional information were all included in an electronic questionnaire that they had to fill out. Results: This study’s findings show that, although 43.2% of participants exhibited high levels of self-compassion, burnout and secondary traumatic stress were at low-to-moderate levels among the participants. Apart from the secondary traumatic stress and humanity dimensions, both the dimensions and the overall self-compassion scale showed a strong relationship with the aspects of professional quality of life. Burnout and secondary traumatic stress were significantly reduced, and compassion fulfilment were increased in environments that were supportive, socially supportive, work-related, hobby-filled, and religious. Conclusions: The integration of self-compassion into a comprehensive and methodical approach to employee wellness has the potential to enhance the physical and mental health of workers in healthcare environments. Full article

Background: Platinum-based chemotherapy significantly increases the risk of nausea and vomiting, which can impair the treatment’s efficacy and the patient’s quality of life. This meta-analysis examines the incidence and risk factors of platinum-based chemotherapy-induced nausea and vomiting (PINV) in patients treated with this chemotherapy. Methods: This systematic review and meta-analysis were conducted in accordance with the PRISMA 2020 guidelines. We conducted a literature search in the databases PubMed, Embase, Web of Science, WanFang, China Science and Technology Journal Database (VIP), China National Knowledge Infrastructure (CNKI), and Chinese Medical Association Journal Database (CMAJD) through to 20 January 2025. Studies that reported the incidence and identified risk factors of nausea and vomiting specifically in patients receiving platinum-based chemotherapy were included in the review. The data were extracted independently by two reviewers. The odds ratios (ORs) for each risk factor were calculated from the included studies. Sensitivity analyses and additional subgroup analyses were performed to ensure the robustness of our findings. Results: This meta-analysis included 32 studies involving 14,207 participants. Female sex (OR = 2.363, 95% CI = 1.363–4.096, p = 0.002), anxiety (OR = 1.689, 95% CI = 1.057–2.700, p = 0.028), fatigue (OR = 1.413, 95% CI = 1.145–1.744, p = 0.001), motion sickness (OR = 1.816, 95% CI = 1.266–2.605, p = 0.001), and a history of vomiting during chemotherapy (OR = 2.728, 95% CI = 1.468–5.069, p = 0.002) were significantly associated with an increased risk of PINV. Conclusion: Female sex, anxiety, fatigue, motion sickness, and a history of vomiting during chemotherapy increase the risk of PINV during platinum-based treatments. Full article

Background: Phenylketonuria (PKU) is a rare metabolic disorder requiring lifelong dietary treatment. Adolescents and young adults face unique challenges in managing the condition, often compromising adherence and psychological well-being. This study aimed to explore coping strategies used by patients to manage their condition and their associations with dietary adherence, PKU-related symptoms, and quality of life (QoL) in young individuals with PKU. Methods: A cross-sectional study was conducted with 21 adolescents and young adults (13–25 years) with classical PKU, followed at the Unit of Inherited Metabolic Diseases in Padua, Italy. Participants completed questionnaires assessing dietary adherence, QoL, and coping. Biochemical data were collected from medical records. Results: Only 57.1% fully adhered to the diet; social barriers like embarrassment and school/work environments hindered adherence. Adolescents reported more irritability and concentration difficulties, while young adults reported greater fatigue. QoL was moderately impacted. Avoidance coping was more frequent in young adults and correlated with irritability and lower QoL. Transcendence-oriented coping was linked to fewer insomnia symptoms. Conclusions: Coping strategies influence symptom experience and QoL in PKU. Integrating psychological support and personalized care into routine treatment is essential to improve adherence and support patients through the transition to adulthood. Full article

Background: Sarcopenia, defined as the progressive loss of skeletal muscle mass and strength, is a critical predictor of morbidity and mortality in patients with cirrhosis. In chronic liver disease, sarcopenia exacerbates adverse clinical outcomes and deteriorates quality of life. Physical activity, particularly resistance training, has demonstrated beneficial effects in reversing muscle depletion in various chronic conditions. Aim: This systematic review aimed to evaluate the impact of resistance training on sarcopenia among cirrhotic patients, with a focus on both pre-liver transplant and post-liver transplant populations, to improve clinical outcomes and enhance quality of life. Methods: A systematic review was conducted in accordance with PRISMA 2020 guidelines. PubMed/MEDLINE databases were searched for randomized controlled trials (RCTs) using a standardized search command combining MESH terms and Boolean operators. Studies meeting eligibility criteria and reporting improvements in sarcopenia following resistance training were selected for data extraction. Results: Out of 109 references identified, 12 RCTs were included—10 in pre-transplant and 2 in post-transplant populations. Across studies, resistance training led to measurable improvements in key outcomes: peak VO₂ increased by up to 5.3 mL/kg/min, 6 min walk distance improved by 18–97 m, quadriceps muscle thickness increased by up to 1.05 cm, and grip strength gains ranged from 0.4 to 3.8 kg. Postoperative studies reported reductions in fatigue severity scores and length of hospital stay, along with improvements in respiratory pressures and peripheral muscle strength. Conclusions: Resistance training is effective in ameliorating sarcopenia in cirrhotic patients, thereby enhancing pre-transplant status and postoperative quality of life. Clinically, structured exercise programs should be routinely implemented. Full article