bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Vaporization Rate and Flame Shape of Nonspherical Droplets
Authors: Palmore John 
Published: February 2022

Abstract
Motivated by the study of spray combustion, this work addresses the combustion of nonspherical droplets. The combustion of spray is usually understood through the theory of droplet combustion, and improving this latter theory is the narrow aim of this work. This work uses perturbation theory to derive a novel model for the vaporization of nonspherical droplets. Compared to previous efforts in this area, the work uses a physics-based approach by incorporating ideas from the asymptotic analysis of Taylor and Acrivos (1964, “On the Deformation and Drag of a Falling Viscous Drop at Low Reynolds Number,” J. Fluid Mech. 18(3), pp. 466–476). The perturbation strategy expands the droplet shape using spherical harmonics, and the theory characterizes the shape of the droplet via the Weber number. The introduction of this parameter is key as it is a parameter that can be easily measured in experiments, and thus it can be used to connect the theoretical results with application. The perturbation analysis is performed based around the classical solution of spherical droplet combustion in quiescent flow. The theory indicates that the effect of droplet deformation can be accounted for by a correction to the droplet combustion rate that is a simple polynomial function of the droplet Weber number. Results are compared to existing literature, and it confirms the established trend that deformed droplets vaporize faster than spherical droplets. Analysis of the flame shape reveals that the flame remains nearly spherical; however, the mean flame standoff changes with droplet shape. The extension of the theory to high Reynolds number conditions is briefly discussed.
A Comparison Between Hardness-Scaling and Ball-Indentation Techniques on Predicting Stress/Strain Distribution and Failure Behavior of Resistance Spot Welded Advanced High Strength Steel
Authors: Zhang Shiping , Ghatei-Kalashami Ali , Midawi Abdelbaset R. H. , Zhou Norman Y. 
Published: February 2022

Abstract
To accurately model the resistance spot welding (RSW) joint in finite element analysis (FEA), the constitutive behavior of materials in various weld regions such as heat-affected zone (HAZ) should be measured. Due to the sharp temperature gradient through RSW specimens, microstructural and corresponding mechanical properties of weld regions are different. Additionally, the size of RSW is small; hence, it is challenging to directly measure the stress–strain curve of materials. In this regard, hardness-scaling and ball-indentation techniques are among the popular methods to in-directly measure the stress–strain curve of these materials. However, the effectiveness of these two techniques on predicting the stress/strain distribution and failure behavior of resistance spot welded advanced high strength steels (AHSS) is not clear. In the present work, the stress–strain curves obtained through hardness-scaling and ball-indentation techniques have been compared. The stress/strain distribution and failure behavior of the resistance spot welded AHSS specimen have been simulated by the stress–strain data obtained using the two methods. The simulation results have been compared with experimental analysis. The results showed that both methods can accurately predict the failure location. With the comparison of FEA results with experiment analysis, it was shown that the ball-indentation method provides slightly better predictions of failure behavior compared to the hardness-scaling method. However, the harness scaling method is a simple and convenient technique, which can be implemented as a qualitative analysis for the failure behavior of RSW joints.
Characterization and Finite Element Modeling for Thermoset Resin of Carbon Fiber Prepregs During Curing
Authors: Feng Yuncong , Zheng Weike , Zhao Zizhao , Liang Biao , Ye Haitao , Ge Qi , Zhang Xiangyi , Zhang Weizhao 
Published: February 2022

Abstract
In this study, an epoxy resin, YZ-05, designed specifically for carbon fiber reinforced polymer prepregs, was characterized and modeled. A degassing method for the highly viscous YZ-05 was established for specimen preparation. To numerically model the behavior of YZ-05 in curing, several components, including the heat transfer, curing kinetics, and viscoelastic constitutive law ones, were developed, and the corresponding material properties to be input were tested. As YZ-05 shows severe creep at high temperature under mechanical loading, the combination of digital image correlation (DIC) and thermography technique was utilized to obtain its thermal expansion and chemical shrinkage. In the aspects of viscoelastic behavior, stress relaxation tests were performed based on time–temperature superposition principle with a numerical method to calculate shift factors. After development and input identification, these modeling components for YZ-05 resin were integrated and the modeling results were validated using experiments, where bending of resin beams was induced during curing.
Design and Experimental Verification of a Parallel Hip Exoskeleton System for Full-Gait-Cycle Rehabilitation
Authors: Wang Xiangyang , Guo Sheng , Qu Bojian , Song Majun , Wang Peiyi , Liu Du-Xin 
Published: February 2022

Abstract
Rehabilitation with exoskeletons after hip joint replacement is a tendency to achieve efficient recovery of people to rebuild their human motor functions. However, the kinematic mismatch between the kinematic and biological hip is a problem in most existing exoskeletons that can cause additional stress in the hip. To avoid secondary damage, the misalignment between the mechanical and biological hip joint of an exoskeleton must be compensated. This paper introduces a novel hip exoskeleton system based on parallel structure. The exoskeleton can inherently address the kinematic mismatch by introducing additional kinematic redundancy, while requiring no additional kinematic components and volumes. To achieve bidirectional full-gait-cycle walking assistance, a remote actuation system is designed for power delivery, and a control scheme is proposed to reject disturbances caused by gait dynamics during walking exercises. Human testing was carried out to evaluate the performance of the system. The results show that the exoskeleton has good human–machine kinematic compatibility and can achieve promising force tracking in the presence of gait dynamics.
Prediction of Short-Term Photovoltaic Power Via Self-Attention-Based Deep Learning Approach
Authors: Li Jie , Niu Huimeng , Meng Fanxi , Li Runran 
Published: February 2022

Abstract
Photovoltaic (PV) is characterized by random and intermittent. As increasing popularity of PV, it makes PV power prediction increasingly significant for efficiency and stability of the power grid. At present, prediction models of PV power based on deep learning show superior performance, but they ignore the interdependent mechanism of prediction error along the input characteristics of the neural network. This paper proposed a self-attention mechanism (SAM)-based hybrid one-dimensional convolutional neural network (1DCNN) and long short-term memory (LSTM) combined method (named 1DCNN-LSTM-SAM). In the proposed model, SAM redistributes the neural weights in 1DCNN-LSTM, and then 1DCNN-LSTM further extracts the space-time information of effective PV power. The polysilicon PV arrays data in Australia are employed to test and verify the proposed model and other five competition models. The results show that the application of SAM to 1DCNN-LSTM improves the ability to capture the global dependence between inputs and outputs in the learning process and the long-distance dependence of its sequence. In addition, mean absolute percentage error of the 1DCNN-LSTM-SAM under sunny day, partially cloudy day, and cloudy day weather types has increased by 24.2%, 14.4%, and 18.3%, respectively, compared with the best model among the five models. Furthermore, the weight distribution mechanism of self-attention to the back end of LSTM was analyzed quantitatively and the superiority of SAM was verified.
Evaluation of the Effectiveness of Base Insulation on the Productivity of a Packed Bed Solar Air Heater
Authors: Verma Sunirmit , Das Ranjan 
Published: February 2022

Abstract
Effect of bottom surface thermal energy loss for a packed bed solar air heater is investigated using both one-dimensional transient and steady-state models. While the former is solved numerically, closed-form solution is obtained for the latter. The effect of variation in base insulation thickness on the system output is studied. For a given bottom insulation thickness, the dependence of its effectiveness on various thermo-geometric parameters is also analyzed. It is observed that a collector with an uninsulated base loses about 60% of the available incident solar energy. In comparison, when the base insulation is as thick as the base wall, i.e., 50 mm here, the base loss fraction drops to nearly 6%, thus highlighting the importance of base insulation. Further, it is seen that the efficiency of a particular base insulation thickness lessens with larger length and width of collector, and rises with a larger mass flowrate of air flowing through it. This work presents a mathematical tool to calculate appropriate insulation thermal resistance to be applied at the base of packed bed solar air heaters that yields the best possible thermal performance alongside minimum insulation cost.
Considerations for the Use of Consumer-Grade Wearables and Smartphones in Population Surveillance of Physical Activity
Authors: Strain Tessa , Wijndaele Katrien , Pearce Matthew , Brage Søren 
Published: February 2022

As smartphone and wearable device ownership increase, interest in their utility to monitor physical activity has risen concurrently. Numerous examples of the application of wearables in clinical and epidemiological research settings already exist. However, whether these devices are all suitable for physical activity surveillance is open for debate. In this commentary, we respond to a commentary by Mair et al. (2021) and discuss four key issues specifically relevant to surveillance that we believe need to be tackled before consumer wearables can be considered for this measurement purpose: representative sampling, representative wear time, validity and reliability, and compatibility between devices. A recurring theme is how to deal with systematic biases by demographic groups. We suggest some potential solutions to the issues of concern such as providing individuals with standardized devices, considering summary metrics of physical activity less prone to wear time biases, and the development of a framework to harmonize estimates between device types and their inbuilt algorithms. We encourage collaborative efforts from researchers and consumer wearable manufacturers in this area. In the meantime, we caution against the use of consumer wearable device data for inference of population-level activity without the consideration of these issues.
Getting a Grip on Strength Measurement in Children (6–13 Y): Impact of Typical Error of Measurement
Authors: Buck Rob , Lambert Michael Ian 
Published: February 2022

Purpose: To identify the smallest change in handgrip strength (HGS) in children that can be considered of practical significance. Method: A total of 290 male and female children, aged 6–13 years, performed a HGS testing protocol 3 times within a 7-day period. The typical error of measurement (TE), coefficient of variation, and smallest worthwhile change (SWC) were calculated for each sex and age group (grade). Results: The TE for the combined group of grade 1 to 7 children was 1.3 kg. Changes in HGS associated with a small change were 1.3 kg, making it difficult for the HGS test to detect these changes. The TE was less than the medium (3.3 kg) and large (5.3 kg) changes in HGS for all the grades and sexes, making changes of these magnitudes more interpretable as they exceed the “noise” (TE) of the measurement. Conclusion: Changes in HGS greater than the TE and SWC can be considered real changes of practical significance. This provides researchers with an extra level of analysis when trying to determine the practical relevance of the observed changes.
Evaluation of a stand-alone mobile mindfulness app in people experiencing infertility: the protocol for an exploratory randomised controlled trial (MoMiFer-RCT)
Authors: Boedt Tessy , Willaert Nele , Lie Fong Sharon , Dancet Eline , Spiessens Carl , Raes Filip , Matthys Christophe , Van der Gucht Katleen 
Published: February 2022

IntroductionInfertility and its treatment bring a considerable emotional burden. Increasing evidence demonstrates the effectiveness of smartphone-delivered mindfulness apps for reducing symptoms of emotional distress in both clinical and non-clinical populations. Evidence on this topic in women, men and couples experiencing infertility is currently under-represented. The aim of the MoMiFer study is, therefore, to investigate the efficacy of a stand-alone mobile mindfulness app on symptoms of emotional distress and fertility-related quality of life in people experiencing infertility.Methods and analysisThis study is an exploratory randomised controlled trial (RCT) with open enrollment. The primary outcomes are symptoms of emotional distress and fertility-related quality of life. Secondary outcomes are mindfulness skills, repetitive negative thinking, self-compassion, user-rated quality of the stand-alone mobile mindfulness app and use of the app. Experience sampling method and standardised self-report questionnaires are combined within a repeated measures design to measure the effects of the stand-alone mobile mindfulness app on the primary and secondary outcomes, apart from the use of the app. The latter will be evaluated through app tracking. People, including women, men and couples, experiencing infertility (n=60) will be randomised to an intervention group receiving the stand-alone mobile mindfulness app for 3 months or a wait-list control group. The app follows the format and content of Mindfulness-Based Stress Reduction. Data will be collected at baseline, at 1.5 months and 3 months after randomisation. Analysis will be according to intention to treat and based on general linear modelling and multilevel mixed-effects modelling.Ethics and disseminationThis study received approval from the Medical Ethical Committee of the Leuven University Hospital (Belgium). The findings of this exploratory RCT will be disseminated through presentations at public lectures, scientific institutions and meetings, and through peer-reviewed scientific articles.Trial registration numberNCT04143828.
Sunshine on KOLs: assessment of the nature, extent and evolution of financial ties between the leaders of professional medical associations and the pharmaceutical industry in France from 2014 to 2019: a retrospective study
Authors: Clinckemaillie Marie , Scanff Alexandre , Naudet Florian , Barbaroux Adriaan 
Published: February 2022

ObjectiveTo investigate the financial relationships between key opinion leader (KOL) or non-KOL physicians and pharmaceutical and device companies in France.DesignRetrospective and descriptive study.SettingAll doctors practising in France, with a focus on 548 KOLs (board members of the professional medical associations that published guidelines in 2018–2019, identified on the associations’ websites between 2018 and 2020). Ties were collected from the ‘Transparency in Healthcare’ database.Main outcome measuresThe number and the value of gifts from 2014 to 2019, and of remunerations and contractual agreements from 2017 to 2019.ResultsKOLs represented 0.24% of the total number of physicians in France. The total value of gifts declared in the French database for all physicians amounted to €818M (US$936M, £741M). At least one gift was declared for 83% of KOLs. KOLs’ gifts represented 0.68% of the total number of gifts to physicians and 1.5% of the total value of gifts, with a mean of €3700 per capita per year.The total value of contractual agreements declared for all physicians amounted to €125M. Contractual agreements involving the KOLs represented 0.72% of the number of contractual agreements with physicians and 2.5% of the value of the agreements, with a mean of €1900 per capita per year.A total of €156M in remunerations were declared for all physicians. KOL remunerations represented 2.3% of the number of physician remunerations and 4.4% of the total value of the remunerations paid to physicians, with a mean of €4100 per capita per year.Almost all professional medical associations (99%) had at least one KOL in their board with a financial tie to the industry, but the amount varied widely among the associations.ConclusionFinancial relationships between KOLs and the industry in France are extensive. KOLs have much more financial ties than non-KOL practitioners.
Associations between adverse childhood experiences, attitudes towards COVID-19 restrictions and vaccine hesitancy: a cross-sectional study
Authors: Bellis Mark A , Hughes Karen , Ford Kat , Madden Hannah C E , Glendinning Freya , Wood Sara 
Published: February 2022

ObjectivesAdverse childhood experiences (ACEs) can affect life-course health and well-being, including risk-taking behaviour and trust. This study explored associations between ACEs and trust in health information on COVID-19, attitudes towards and compliance with COVID-19 restrictions and vaccine hesitancy.DesignNational cross-sectional telephone survey using a sample of landline and mobile numbers stratified by Health Board, deprivation quintile and age group.SettingHouseholds in Wales during national COVID-19 restrictions (December 2020 to March 2021).Participants2285 Welsh residents aged ≥18 years.MeasuresNine ACEs; low trust in National Health Service (NHS) COVID-19 information; supporting removal of social distancing and mandatory face coverings; breaking COVID-19 restrictions; and vaccine hesitancy (rejection or uncertainty of vaccination).ResultsIncreasing ACE counts were independently related to low trust in NHS COVID-19 information, feeling unfairly restricted by government and ending mandatory face coverings. High ACE counts (4+ vs 0 ACEs) were also associated with supporting removal of social distancing. Breaking COVID-19 restrictions increased with ACE count with likelihood doubling from no ACEs to 4+ ACEs. Vaccine hesitancy was threefold higher with 4+ ACEs (vs 0 ACEs) and higher in younger age groups. Thus, modelled estimates of vaccine hesitancy ranged from 3.42% with no ACEs, aged ≥70 years, to 38.06% with 4+ ACEs, aged 18–29 years.ConclusionsACEs are common across populations of many countries. Understanding how they impact trust in health advice and uptake of medical interventions could play a critical role in the continuing response to COVID-19 and controlling future pandemics. Individuals with ACEs suffer greater health risks throughout life and may also be excluded from interventions that reduce infection risks. While pandemic responses should consider how best to reach those suffering from ACEs, longer term, better compliance with public health advice is another reason to invest in safe and secure childhoods for all children.
Prevalence and associated factors of lower extremity musculoskeletal disorders among manufacturing workers: a cross-sectional study in China
Authors: Jin Xu , Dong Yidan , Wang Fujiang , Jiang Ping , Zhang Zhongbin , He Lihua , Forsman Mikael , Yang Liyun 
Published: February 2022

ObjectiveTo survey the prevalence of lower extremity musculoskeletal disorders (MSDs) among Chinese manufacturing workers, and to identify the associated factors.DesignObservational study with cross-sectional design.SettingA self-administered questionnaire survey was conducted in four manufacturing factories in China.Participants7908 manufacturing workers were included in this study after excluding non-conforming personnel.Outcome measuresIndividual and work-related information, and MSDs in the whole leg and knee region were measured by the anonymous self-administered questionnaire. Individual and work-related factors associated with MSDs and their effects were identified through multivariate logistic regression.ResultsOf all respondents, 3241 (41.0%) reported having had lower extremity MSDs in the recent 12 months, and for the knees, ankles/feet and hips/thighs were 29.5%, 23.9% and 16.7%, respectively. After confounder-adjusted single-factor analysis, 22 variables (of 24) were significantly related to the disorders. Factors like always kneeling/squatting for long periods, always standing for long periods and often lifting in an uncomfortable position were shown to have higher risks, with ORs of 2.77 (95% CI: 2.33 to 3.30), 2.30 (1.96 to 2.69) and 2.25 (2.04 to 2.47). Comparable results were found on knee disorders. The final model included 15 variables of demography, biomechanics and work organisation. The following factors showed increased risks of lower extremity MSDs: being female, being older, longer working years, higher body mass index (BMI), keeping the same posture for a long time, awkward position, shift work and monotonous work. Whereas having enough breaks reduced the risk.ConclusionThe prevalence of lower extremity MSDs among Chinese manufacturing workers is high. The most commonly affected body regions were the knees and ankles/feet. Multiple factors were found associated with lower extremity MSDs including age, BMI, work experience, work organisations, physical ergonomics exposures, etc.
Clinical outcomes of children with rheumatic heart disease
Authors: Zimmerman Meghan , Kitooleko Samalie , Okello Emmy , Ollberding Nicholas , Sinha Pranava , Mwambu Tom , Sable Craig , Beaton Andrea , Longenecker Chris , Lwabi Peter 
Published: February 2022

ObjectiveTo evaluate the long-term clinical outcomes of children with rheumatic heart disease (RHD) in Uganda, and determine characteristics that predict adverse outcomes.MethodsThis retrospective cohort study evaluated the risk of death in Ugandan children with clinical RHD from 2010 to 2018; enrolling children aged 5–18 years old from an existing registry. Demographic data and clinical data (baseline complications, RHD severity, cardiac interventions) were collected. The primary outcome was survival. Univariable and multivariable hazard ratios (HR) were obtained from Cox proportional hazards regression. Survival probabilities were developed using Kaplan-Meier curves; log-rank tests compared survival based on cardiac interventions, disease severity and time of enrolment.Results612 cases met inclusion criteria; median age 12.8 years (IQR 5.3), 37% were male. Thirty-one per cent (187 of 612) died during the study period; median time to death 7.8 months (IQR 18.3). In univariable analysis, older age (HR 1.26, 95% CI=1.0 to 1.58), presence of baseline complications (HR 2.06, 95% CI=1.53 to 2.78) and severe RHD (HR 5.21, 95% CI=2.15 to 12.65) were associated with mortality. Cardiac intervention was associated with a lower risk of mortality (HR 0.06, 95% CI=0.02 to 0.24). In multivariable models, baseline complications (HR 1.78, 95% CI=1.31 to 2.41), severe RHD (HR 4.58, 95% CI=1.87 to 11.23) and having an intervention (HR 0.05, 95% CI=0.01 to 0.21) remained statistically significant. Kaplan-Meier survival curves demonstrated >25% mortality in the first 30 months, with significant differences in mortality based on intervention status and severity of disease.ConclusionsThe mortality rate of children with clinical RHD in Uganda exceeds 30%, over an 8-year time frame, despite in-country access to cardiac interventions. Children at highest risk were those with cardiac complications at baseline and severe RHD.