102 research outputs found

    Long-time Evolution of Interfacial Structure of Partial Wetting

    Full text link
    When a solid plate is withdrawn from a partially wetting liquid, a liquid layer dewets the moving substrate. High-speed imaging reveals alternating thin and thick regions in the entrained layer in the transverse direction at steady state. This paper systematically compares this situation to the reversed process, forced wetting, where a solid entrains an air layer along its surface as it is pushed into a liquid. To quantify the absolute thickness of these steady-state structures precisely, I have developed an optical technique, taking advantage of the angle dependence of interference, combined with a method based on a maximum likelihood estimation. The data show that the thicknesses of both regions of the film scale with the capillary number, Ca. In addition, a new region is observed during onset which differs from the behavior predicted by previous models.Comment: 14 pages, 17 figure

    The effect of PVD layout on the consolidation characteristics of dredged slurry under vacuum preloading

    Get PDF
    Vacuum preloading coupled with prefabricated vertical drains (PVDs) has been widely used to improve the property of the dredged slurry. However, the effect of PVD layout on slurry consolidation characteristics remains poorly understood. This study conducted two vacuum preloading model tests—with single and dual PVDs. Particle image velocimetry (PIV) was used to directly observe the slurry displacements and strain paths. The test results revealed that the slurry consolidation characteristics were similar under different PVD layouts in the early stage of vacuum preloading. However, in the mid-stage, the effect of dual PVDs led to a significant reduction and increased dispersion of the slurry horizontal displacement. This, in turn, resulted in a thinner clogging zone and a subsequent decrease in vacuum pressure loss. Consequently, the slurry near the PVDs experienced an extended period of consolidation deformation. During the later stage, the single PVD model test exhibited a distinct zone of both vertical and horizontal compression in the slurry, while under dual PVDs, the slurry primarily underwent vertical compression and horizontal extension. The study also provided the relationship between the clogging zone thickness and time, which provided a reference for theoretical consolidation calculations

    FREPA: An Automated and Formal Approach to Requirement Modeling and Analysis in Aircraft Control Domain

    Full text link
    Formal methods are promising for modeling and analyzing system requirements. However, applying formal methods to large-scale industrial projects is a remaining challenge. The industrial engineers are suffering from the lack of automated engineering methodologies to effectively conduct precise requirement models, and rigorously validate and verify (V&V) the generated models. To tackle this challenge, in this paper, we present a systematic engineering approach, named Formal Requirement Engineering Platform in Aircraft (FREPA), for formal requirement modeling and V\&V in the aerospace and aviation control domains. FREPA is an outcome of the seamless collaboration between the academy and industry over the last eight years. The main contributions of this paper include 1) an automated and systematic engineering approach FREPA to construct requirement models, validate and verify systems in the aerospace and aviation control domain, 2) a domain-specific modeling language AASRDL to describe the formal specification, and 3) a practical FREPA-based tool AeroReq which has been used by our industry partners. We have successfully adopted FREPA to seven real aerospace gesture control and two aviation engine control systems. The experimental results show that FREPA and the corresponding tool AeroReq significantly facilitate formal modeling and V&V in the industry. Moreover, we also discuss the experiences and lessons gained from using FREPA in aerospace and aviation projects.Comment: 12 pages, Published by FSE 202

    An evaluation of EQ-5D-3L health utility scores using five country-specific tariffs in a rural population aged 45-69 years in Hua county, Henan province, China.

    Get PDF
    BACKGROUND: This study aims to compare the performance of the recently developed Chinese (city) tariff of the EQ-5D-3L against the UK, US, Japanese and Korean tariffs in a general rural population in China. METHODS: From November 2015 to September 2016, 12,085 permanent residents aged 45-69 from 257 villages randomly selected from Hua County, Henan Province, China, were interviewed using EQ-5D-3L, and a one-on-one questionnaire investigation was used to collect data on factors associated with HRQOL. The health utility scores were calculated using the UK, US, Japanese, Korean and Chinese (city) tariffs. The agreement, known-groups validity and sensitivity of these five tariffs were evaluated. Transition scores for pairs of observed EQ-5D-3L health states were calculated and compared. RESULTS: The Korean tariff yielded the highest mean health utility score (0.963), followed by the Chinese (city) (0.948), US (0.943), UK (0.930) and Japanese (0.921) tariffs, but the differences in the scores of any two tariffs did not exceed the MCID. The Chinese (city) tariff showed higher ICC values (ICCs> 0.89, 95% CI:0.755-0.964) and narrower limits of agreement (0.099-0.167) than the Korean tariff [(ICCs> 0.71, 95% CI:0.451-0.955); (0.146-0.253)]. The Chinese (city) tariff had a higher relative efficiency and effect size statistics in 10 out of 11 variables as compared to the UK, US and Japanese tariffs. The Chinese (city) tariff (0.215) was associated with moderate mean absolute transition scores compared with the UK (0.342), US (0.230), Japanese (0.149) and Korean (0.189) tariffs for 1485 observed pairs of the EQ-5D-3L health states. CONCLUSIONS: Health utility scores derived from the five tariffs differed. The Chinese (city) tariff was the most suitable of these tariffs and was without obvious weakness. We recommend adopting the Chinese (city) tariff when applying EQ-5D-3L to assess quality of life among the elderly in China's agricultural region with socio-economic status similar to Hua County. Results of this study had provided a crucial basis for health surveys, health promotion projects, health intervention trials, and health economic evaluation taking HRQOL as a target in rural areas of China

    Effects of virtual exposure to urban greenways on mental health

    Get PDF
    Urban greenways (UGW) are increasingly recognized as vital components of urban green infrastructure (UGI). While existing research has provided empirical evidence on the positive impacts of UGW on physical health, studies focusing on the effects on mental health remain limited. Moreover, previous investigations predominantly compare UGW as a whole with other built environments, neglecting the influence of specific vegetation designs along UGW on mental health. To address this research gap, we conducted a randomized controlled experiment to examine the impact of vegetation design along UGW on stress reduction and attention restoration. A total of 94 participants were randomly assigned to one of four UGW conditions: grassland, shrubs, grassland and trees, or shrubs and trees. Utilizing immersive virtual reality (VR) technology, participants experienced UGW through a 5-min video presentation. We measured participants’ subjective and objective stress levels and attentional functioning at three time-points: baseline, pre-video watching, and post-video watching. The experimental procedure lasted approximately 40 minutes. Results of the repeated-measures ANOVA revealed that participants experienced increased stress and mental fatigue after the stressor and decreased levels following the UGW intervention. Furthermore, between-group analyses demonstrated that the shrubs group and the grassland and trees group exhibited significantly greater stress reduction than the grassland group. However, there are no significant differences in attention restoration effects between the four groups. In conclusion, virtual exposure to UGW featuring vegetation on both sides positively affected stress reduction and attention restoration. It is recommended that future UGW construction incorporates diverse vegetation designs, including shrubs or trees, instead of solely relying on grassland. More research is needed to explore the combined effects of shrubs and trees on mental health outcomes

    Estás comigo ou contra mim? : o papel moderador da relação treinador-atleta na relação entre grit e engagement desportivo nos atletas

    Get PDF
    Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção de grau de Mestre na especialidade de Psicologia Social e das OrganizaçõesO presente estudo teve como principal objetivo contribuir para o estudo da relação entre treinador e atleta e a testar o seu papel moderador entre na relação entre as variáveis individuais de grit e engagement desportivo dos atletas. Participaram neste estudo 315 atletas de várias modalidades individuais e coletivas. Foi elaborado um questionário aplicado online constituído pela Escala de Relação Treinador-Atleta (CART-Q), a Escala de Grit (GRIT-S) e a Escala de Engagement Desportivo (AEQ). Os resultados demostram que a relação treinador-atleta influencia positivamente o nível de grit e o nível de engagement dos atletas, e evidenciam ainda uma associação positiva entre o nível de grit e o nível de engagement. Verificou-se também que a relação treinador-atleta tem um efeito moderador nos níveis de grit e uma dimensão específica engagement do atleta, a Dedicação. Os resultados são discutidos, analisados e são apresentadas as limitações do estudo, assim como sugestões para estudos futuros.The main goal of this work was to contribute to the study of the relationship between the coach and his athletes and to test its moderating role in the relationship between the individual traits of grit and sport engagement of athletes. A total of 315 Portuguese athletes of both sexes, and diverse collective and individual sports participated in this study. These participants answered an online questionnaire constituted by the Coach-Athlete Relationship (CART-Q), the Grit Scale (GRIT-S) and the Engagement Scale (AEQ). The results showed that the coach-athlete relationship influences positively the levels of grit and sport engagement of the athletes, and also evidence a positive association between the level of grit and the level of engagement. Results also showed that the coach-athlete relationship has a moderator effect on the levels of grit and a specific dimension of engagement, the Dedication. The results are discussed, analyzed and are presented the limitations of the study, as well some suggestions for future studies

    Health-seeking behavior and barriers to treatment of patients with upper gastrointestinal cancer detected by screening in rural China: real-world evidence from the ESECC trial.

    Get PDF
    BACKGROUND: To fully realize efficacy in cancer screening, timely and appropriate treatment for participants with malignant lesions is critical. However, the health-seeking behavior of patients with upper gastrointestinal (G.I.) cancer identified in population-level screening programs in China is unknown. METHODS: A community-based real-world investigation was conducted with 136 upper G.I. cancer patients detected in a large screening cohort in an area of high-risk for upper G.I. cancer in China. Using local medical claims data and semi-structured face-to-face interview, we collected information regarding the clinical treatment regimen and factors which result in the lack of timely and appropriate treatment. FINDINGS: The treatment records for 133 upper G.I. cancer patients were acquired. Among these, 48 (36•09%) patients did not receive treatment within three months of initial diagnosis, and treatment of early-stage cancer was more likely to be delayed. Sixteen patients did not seek further diagnostic testing due to their low health-awareness and socio-economic status. Another 20 participants proactively sought further diagnostic evaluation in health care facilities but were prevented from receiving further treatment due to low sensitivity of given diagnostic test(s), failure to recognize the significance of screening results, and/or lack of basic knowledge of diagnosis and treatment for early cancer on the part of clinicians. The treatment regimen offered to patients depended largely on the level of health care facilities they visited, and non-medical factors were the main reasons for choice of health care facilities. INTERPRETATION: A coordinated, system-based management strategy is urgently needed to support the design of upper G.I. cancer screening programs in rural populations in China. FUNDING: The Charity Project of the National Ministry of Health (201202014), the National Key R & D Program of China (2016YFC0901404), the National Science & Technology Fundamental Resources Investigation Program of China (2019FY101102), and the National Natural Science Foundation of China (82073626)
    corecore