bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study on Flow Behavior and Heat Transfer Enhancement With Distinct Dimpled Gas Turbine Blade Internal Cooling Channel
Authors: Nourin Farah Nazifa , Amano Ryoichi S. 
Published: August 2021

AbstractThe study presents the investigation on heat transfer distribution along a gas turbine blade internal cooling channel. Six different cases were considered in this study, using the smooth surface channel as a baseline. Three different dimples depth-to-diameter ratios with 0.1, 0.25, and 0.50 were considered. Different combinations of partial spherical and leaf dimples were also studied with the Reynolds numbers of 6,000, 20,000, 30,000, 40,000, and 50,000. In addition to the experimental investigation, the numerical study was conducted using a large eddy simulation (LES) to validate the data. It was found that the highest depth-to-diameter ratio showed the highest heat transfer rate. However, the deepest dimpled channel shows the highest pressure drop, which affects the overall thermal performance of the cooling channel. The results showed that the leaf dimpled surface is the best cooling channel based on the highest Reynolds number's heat transfer enhancement and friction factor. However, at the lowest Reynolds number, partial spherical dimples with a 0.25 depth-to-diameter ratio showed the highest thermal performance.
Modeling and Control of Flywheel-Integrated Generators in Split-Shaft Wind Turbines
Authors: Akbari Rasoul , Izadian Afshin 
Published: August 2021

Abstract
This paper introduces the modeling and control of split-shaft drivetrains where the system’s inertia is adjusted to store the energy. Accordingly, a flywheel is mechanically coupled with the rotor of a doubly fed induction generator. The generator is driven by a split-shaft drivetrain that decouples the turbine’s shaft from the shaft of the generator to provide independent control of their angular velocities. Hence, the turbine controller can track the point of maximum power while the generator controller can adjust the generator speed. Accordingly, the flywheel, which is directly connected to the shaft of the generator, is charged and discharged by controlling the generator speed. In this process, the flywheel can modify the electric power generation of the generator on-demand. Since the drivetrain is a split-shaft, the turbine speed is not affected by this energy storing process. This improves the quality of injected power to the grid. The structure of the flywheel energy storage can be simplified by removing its dedicated motor/generator and the power electronics driver. This significant modification can only occur in the split-shaft drivetrain. Two separate supervisory controllers are developed in the form of fuzzy logic regulators to generate a real-time output power reference. Furthermore, small-signal models are developed to analyze and improve the maximum power point tracking controller. Extensive simulation results demonstrate the feasibility of such a system and its improved quality of power generation.
Relationship Between Mechanical Behavior and Microstructure Evolution of Sintered Metallic Brake Pad Under the Impact of Thermomechanical Stress
Authors: Le Tran Hoang-Long , Anne-Lise Cristol , Jérôme Hosdez , Vincent Magnier 
Published: August 2021

Abstract
It is well known that on the brake pad material, the triptych microstructure-properties-solicitations is the key to better understand the phenomena caused by braking stress. The challenging issues are the evolution of this triptych, i.e., the impact of thermal stress and mechanical stress on the microstructure which undoubtedly induces changes in properties. In order to solve the issues without tackling them in all their complexity, this study proposes an experimental approach where physics is decoupled but inspired by the braking sequence in terms of applied temperature gradient and braking loads. Two experimental tests were carried out. The first one is the thermal solicitation test where a temperature gradient from 400 °C to 540 °C was applied to the material. The second one is the thermomechanical test where a compressive load at 20 MPa was applied under the same thermal gradient. The experiment time is fixed for 2 min, equivalent to the time of one braking stroke. The referred material is sintered metallic composite, which is widely used as the brake pad material for high energy railway. As a result, it shows that coupled thermomechanical stress has a greater impact on material properties than decoupled one. This impact is related to the microstructure where graphite inclusions play an important role.
Effectiveness of community outreach screening for glaucoma in improving equity and access to eye care in Nigeria
Authors: Olawoye Olusola Oluyinka , Fawole Olufunmilayo , Ashaye Adeyinka O , Chan Ving Fai , Azuara-Blanco Augusto , Congdon Nathan 
Published: August 2021

PurposeTo determine the effectiveness of community outreach screening for glaucoma in improving equity and access to eye care in Nigeria.MethodologyThis was a prospective study in which two cohort of participants were recruited in Nigeria: 1 from 24 outreach screenings and another from consecutive patients presenting spontaneously to a tertiary eye clinic in Nigeria. Sociodemographic and clinical data were obtained from participants and compared.ResultsOur sample consisted of 120 patients with glaucoma or suspected glaucoma (6.38% of 1881 screenees) recruited from the 24 outreach screenings, and another 123 patients with glaucoma who presented spontaneously at the eye clinic. Participants from the screenings were significantly older (p=0.012), less educated (p<0.001), had lower incomes (p<0.001), lower glaucoma knowledge scores and were less aware of their glaucoma (both p<0.001) and were more likely to be dependent on relations and children (p=0.002) compared with clinic participants. Of the 120 patients identified at the screenings and referred to the clinic for definitive care, 39 (32.5%) presented at the clinic within 3 months. Reasons for poor uptake of referral services were lack of a felt need and lack of money for transportation. Considering only patients who accepted referral, they were still less educated (p<0.001), poorer (p=0.001) and less knowledgeable about glaucoma (p=0.003) than spontaneous clinic presenters.ConclusionOutreach screening improved equity of access but its effects were somewhat reduced by poor uptake of referral care. Interventions such as free transportation and educational efforts may improve the uptake of referral services and maximise equity gains.
Women’s report of mistreatment during facility-based childbirth: validity and reliability of community survey measures
Authors: Leslie Hannah Hogan , Sharma Jigyasa , Mehrtash Hedieh , Berger Blair Olivia , Irinyenikan Theresa Azonima , Balde Mamadou Dioulde , Mon Nwe Oo , Maya Ernest , Soumah Anne-Marie , Adu-Bonsaffoh Kwame , Maung Thae Maung , Bohren Meghan A , Tunçalp Özge 
Published: August 2021

BackgroundAccountability for mistreatment during facility-based childbirth requires valid tools to measure and compare birth experiences. We analyse the WHO ‘How women are treated during facility-based childbirth’ community survey to test whether items mapping the typology of mistreatment function as scales and to create brief item sets to capture mistreatment by domain.MethodsThe cross-sectional community survey was conducted at up to 8 weeks post partum among women giving birth at hospitals in Ghana, Guinea, Myanmar and Nigeria. The survey contained items assessing physical abuse, verbal abuse, stigma, failure to meet professional standards, poor rapport with healthcare workers, and health system conditions and constraints. For all domains except stigma, we applied item-response theory to assess item fit and correlation within domain. We tested shortened sets of survey items for sensitivity in detecting mistreatment by domain. Where items show concordance and scale reliability ≥0.60, we assessed convergent validity with dissatisfaction with care and agreement of scale scores between brief and full versions.Results2672 women answered over 70 items on mistreatment during childbirth. Reliability exceeded 0.60 in all countries for items on poor rapport with healthcare workers and in three countries for items on failure to meet professional standards; brief scales generally showed high agreement with longer versions and correlation with dissatisfaction. Brief item sets were ≥85% sensitive in detecting mistreatment in each country, over 90% for domains of physical abuse and health system conditions and constraints.ConclusionBrief scales to measure two domains of mistreatment are largely comparable with longer versions and can be informative for these four distinct settings. Brief item sets efficiently captured prevalence of mistreatment in the five domains analysed; stigma items can be used and adapted in full. Item sets are suitable for confirmation by context and implementation to increase accountability and inform efforts to eliminate mistreatment during childbirth.
Experiences of Australian primary healthcare nurses in using telehealth during COVID-19: a qualitative study
Authors: James Sharon , Ashley Christine , Williams Anna , Desborough Jane , Mcinnes Susan , Calma Kaara , Mursa Ruth , Stephen Catherine , Halcomb Elizabeth J 
Published: August 2021

ObjectiveThis study sought to explore the experiences of Australian primary healthcare (PHC) nurses in the use of telehealth during COVID-19. Telehealth was defined as the use of any telecommunications mode (eg, telephone and videoconferencing) to deliver healthcare.Design and settingThematic analysis of qualitative interviews undertaken in Australian PHC.ParticipantsTwenty-five PHC nurses who had participated in a national survey about their experiences during COVID-19 were recruited using purposive sampling.MethodsSemistructured telephone interviews were conducted from June to August 2020. Interviews lasted a mean of 38.5 min. They were audio-recorded and transcribed before thematic analysis was undertaken. The consolidated criteria for reporting qualitative research were followed.ResultsFour overarching themes were identified: preparedness, accessibility of telehealth, care experience and impacts on the PHC nurses’ role. Some nurses were experienced in the use of telehealth, while others indicated a lack of preparation and limited appropriate technology to support its use. Telehealth enabled patients to access care but did not support complex clinical assessment. Participants indicated that patient engagement in telehealth was dependent on access and confidence using technology, perceived safety when physically attending the practice and the value they placed on care via telehealth. Many participants expressed frustration about telehealth funding and its impact on facilitating nurses to practise to their full scope.ConclusionTelehealth has provided a means to continue PHC service delivery during COVID-19. While there are advantages to adopting this technology, considerations of the challenges and lessons from this experience are important to inform the future implementation of telehealth initiatives.
Characteristics and outcomes of hospitalised adults with COVID-19 in a Global Health Research Network: a cohort study
Authors: Zhu Julia , Wei Zhongyuan , Suryavanshi Manasi , Chen Xiu , Xia Qian , Jiang Jenny , Ayodele Olulade , Bradbury Brian D , Brooks Corinne , Brown Carolyn A , Cheng Alvan , Critchlow Cathy W , Devercelli Giovanna , Gandhi Vivek , Gondek Kathleen , Londhe Ajit A , Ma Junjie , Jonsson-Funk Michele , Keenan Hillary A , Manne Sudhakar , Ren Kaili , Sanders Lynn , Yu Peter , Zhang Jie , Zhou Linyun , Bao Ying 
Published: August 2021

ObjectiveTo examine age, gender, and temporal differences in baseline characteristics and clinical outcomes of adult patients hospitalised with COVID-19.DesignA cohort study using deidentified electronic medical records from a Global Research Network.Setting/Participants67 456 adult patients hospitalised with COVID-19 from the USA; 7306 from Europe, Latin America and Asia-Pacific between February 2020 and January 2021.ResultsIn the US cohort, compared with patients 18–34 years old, patients ≥65 had a greater risk of intensive care unit (ICU) admission (adjusted HR (aHR) 1.73, 95% CI 1.58 to 1.90), acute respiratory distress syndrome(ARDS)/respiratory failure (aHR 1.86, 95% CI 1.76 to 1.96), invasive mechanical ventilation (IMV, aHR 1.93, 95% CI, 1.73 to 2.15), and all-cause mortality (aHR 5.6, 95% CI 4.36 to 7.18). Men appeared to be at a greater risk for ICU admission (aHR 1.34, 95% CI 1.29 to 1.39), ARDS/respiratory failure (aHR 1.24, 95% CI1.21 to 1.27), IMV (aHR 1.38, 95% CI 1.32 to 1.45), and all-cause mortality (aHR 1.16, 95% CI 1.08 to 1.24) compared with women. Moreover, we observed a greater risk of adverse outcomes during the early pandemic (ie, February–April 2020) compared with later periods. In the ex-US cohort, the age and gender trends were similar; for the temporal trend, the highest proportion of patients with all-cause mortality were also in February–April 2020; however, the highest percentages of patients with IMV and ARDS/respiratory failure were in August–October 2020 followed by February–April 2020.ConclusionsThis study provided valuable information on the temporal trends of characteristics and outcomes of hospitalised adult COVID-19 patients in both USA and ex-USA. It also described the population at a potentially greater risk for worse clinical outcomes by identifying the age and gender differences. Together, the information could inform the prevention and treatment strategies of COVID-19. Furthermore, it can be used to raise public awareness of COVID-19’s impact on vulnerable populations.
Not straightforward: modelling non-linearity in training load and injury research
Authors: Bache-Mathiesen Lena Kristin , Andersen Thor Einar , Dalen-Lorentsen Torstein , Clarsen Benjamin , Fagerland Morten Wang 
Published: August 2021

ObjectivesTo determine whether the relationship between training load and injury risk is non-linear and investigate ways of handling non-linearity.MethodsWe analysed daily training load and injury data from three cohorts: Norwegian elite U-19 football (n=81, 55% male, mean age 17 years (SD 1)), Norwegian Premier League football (n=36, 100% male, mean age 26 years (SD 4)) and elite youth handball (n=205, 36% male, mean age 17 years (SD 1)). The relationship between session rating of perceived exertion (sRPE) and probability of injury was estimated with restricted cubic splines in mixed-effects logistic regression models. Simulations were carried out to compare the ability of seven methods to model non-linear relationships, using visualisations, root-mean-squared error and coverage of prediction intervals as performance metrics.ResultsNo relationships were identified in the football cohorts; however, a J-shaped relationship was found between sRPE and the probability of injury on the same day for elite youth handball players (p<0.001). In the simulations, the only methods capable of non-linear modelling relationships were the quadratic model, fractional polynomials and restricted cubic splines.ConclusionThe relationship between training load and injury risk should be assumed to be non-linear. Future research should apply appropriate methods to account for non-linearity, such as fractional polynomials or restricted cubic splines. We propose a guide for which method(s) to use in a range of different situations.
Exercise-induced hypoxia among emergency department patients admitted for suspected COVID-19
Authors: Davies Peter , Jones Timothy , Bartilotti-Matos Francisca , Crowe Tim , Russell Andrew , Sykes Catie 
Published: August 2021

BackgroundExercise-induced hypoxia (EIH) has been assessed at ED triage as part of an assessment of COVID-19; however, evidence supporting this practice is incomplete. We assessed the use of a 1-minute sit-to-stand exercise test among ED patients admitted for suspected COVID-19.MethodsA case note review of all ED patients assessed for suspected COVID-19 between March and May 2020 at Monklands University Hospital was conducted. Demographic characteristics, clinical parameters, baseline blood tests and radiographic findings, hospital length of stay, intensive care and maximum oxygen requirement were obtained for those admitted. Using logistic regression, the association between EIH at admission triage and COVID-19 diagnosis was explored adjusting for confounding clinical parameters.ResultsOf 127 ED patients admitted for possible COVID-19, 37 were ultimately diagnosed with COVID-19. 36.4% of patients with COVID-19 and EIH had a normal admission chest radiograph. In multivariate analysis, EIH was an independent predictor of COVID-19 (adjusted OR 3.73 (95% CI (1.25 to 11.15)), as were lymphocyte count, self-reported exertional dyspnoea, C-reactive peptide and radiographic changes.ConclusionsThis observational study demonstrates an association between EIH and a COVID-19 diagnosis. Over one-third of patients with COVID-19 and EIH exhibited no radiographic changes. EIH may represent an additional tool to help predict a COVID-19 diagnosis at initial presentation and may assist in triaging need for admission.
Review of COVID-19 vaccine subtypes, efficacy and geographical distributions
Authors: Francis Andre Ian , Ghany Saudah , Gilkes Tia , Umakanthan Srikanth 
Published: August 2021

AbstractAs of 1 May 2021, there have been 152 661 445 Covid-19 cases with 3 202 256 deaths globally. This pandemic led to the race to discover a vaccine to achieve herd immunity and curtail the damaging effects of Covid-19. This study aims to discuss the most recent WHO-approved Covid-19 vaccine subtypes, their status and geographical scheduled updates as of 4 May 2021. The keywords “Covid-19, Vaccines, Pfizer, BNT162b2, AstraZeneca, AZD1222, Moderna, mRNA-1273, Janssen, Ad26.COV2.S” were typed into PubMed. Thirty Two relevant PubMed articles were included in the study. The vaccines discussed are Pfizer/BNT162b2, Moderna Vaccine/mRNA1273, AstraZeneca/AZD122/ChAdOx1 n-CoV-19 and the Janssen vaccines/Ad26.COV2.S, as well as their platforms, trials, limitations and geographical distributions. As of 16 May 2021, the number of countries that have approved the use of the following vaccines is Pfizer in 85, Moderna in 46, Oxford/AstraZeneca in 101, and Janssen in 41.
Policy incoherence and tobacco control in Indonesia: an analysis of the national tobacco-related policy mix
Authors: Kramer Elisabeth , Ahsan Abdillah , Rees Vaughan W 
Published: August 2021

IntroductionIndonesia has a high smoking prevalence that has not diminished significantly since 1990. Considering this, we aim to summarise the existing national tobacco-related policy mix and explore markers of policy incoherence in tobacco control between 2014 and 2020.MethodsWe conducted (1) a review and synthesis of Indonesian tobacco-related legislation and regulations; (2) a systematic search and synthesis of related literature and news reporting; and (3) interviews with tobacco control activists and academics to understand political will towards tobacco control regulations and the tobacco industry.ResultsIndonesia’s existing tobacco-related policy mix lies across the president’s office, six national ministries and one independent agency. However, current responsibility lies primarily with four government ministries: Ministries of Health, Finance, Communication and Information, and Trade and Industry, with the Ministry of Finance most active. Evidence demonstrates that official interministerial collaboration was lacking from 2014 to 2020 and suggests that institutional will to introduce more effective tobacco control varies considerably between different arms of government.DiscussionPolitical will differs according to ministerial mandates and priorities, fostering a fragmented policy approach and undermining the development of a coherent response. Without political will from the president or national parliament to create an overarching framework for tobacco control, either via ratification of the Framework Convention on Tobacco Control or another mechanism, there remains no formal impetus for intragovernmental cooperation. Nonetheless, this analysis reveals some government progress and ‘pressure points’ that advocates can focus on to promote tobacco control policies within the current policy mix.
Distinguish the f(T) model from $$\Lambda $$CDM model with Gravitational Wave observations
Authors: Zhang Yi , Zhang Hongsheng 
Published: August 2021

AbstractSeparately, neither electromagnetic (EM) observations nor gravitational wave (GW) observations can distinguish between the f(T) model and the $$\Lambda $$
Λ
CDM model effectively. To break this degeneration, we simulate the GW measurement based on the coming observation facilities, explicitly the Einstein Telescope. We make cross-validations between the simulated GW data and factual EM data, including the Pantheon, H(z), BAO and CMBR data, and the results show that they are consistent with each other. Anyway, the EM data itself have the $$H_0$$

H
0

tension problem which plays critical role in the distinguishable problem as we will see. Our results show that the GW$$+$$
+
BAO$$+$$
+
CMBR data could distinguish the f(T) theory from the $$\Lambda $$
Λ
CDM model in $$2\sigma $$

2
σ

regime.
Feedback control method to suppress stick-slip in drill-strings featuring delay and actuation constraints
Authors: MacLean James D. J. , Vaziri Vahid , Aphale Sumeet S. , Wiercigroch Marian 
Published: August 2021

AbstractIn this work, performance of a modified-integral resonant controller with integral tracking is investigated numerically under the effects of actuator delay and actuation constraints. Actuation delay and constraints naturally limit controller performance, so much so that it can cause instabilities. A 2-DOF drill-string m with nonlinear bit–rock interactions is analysed. The aforementioned control scheme is implemented on this system and analysed under the effects of actuation delay and constraints and it is found to be highly effective at coping with these limitations. The scheme is then compared to sliding-mode control and shows to be superior in many regimes of operation. Lastly, the scheme is analysed in detail by varying its gains as well as varying system parameters, most notably that of actuation delay.
Buckling Design of Axially Compressed Cylindrical Shells Based on Energy Barrier Approach
Authors: Fan Haigui , Gu Wenguang , Li Longhua , Liu Peiqi , Hu Dapeng 
Published: August 2021

Buckling design of axially compressed cylindrical shells is still a challenging subject considering the high imperfection-sensitive characteristic in this kind of structure. With the development of various design methods, the energy barrier concept dealing with buckling of imperfection-sensitive cylindrical shells exhibits a promising prospect in recent years. In this study, buckling design of imperfection-sensitive cylindrical shells under axial compression based on the energy barrier approach is systematically investigated. The methodology about buckling design based on the energy barrier approach is described in detail first taking advantage of the cylindrical shells whose buckling loads have been extensively tested. Then, validation and discussion about this buckling design method have been carried out by the numerical and experimental analyses on the cylindrical shells with different geometrical and boundary imperfections. Results in this study together with the available experimental data have verified the reliability and advantage of the buckling design method based on energy barrier approach. A design criterion based on the energy barrier approach is therefore established and compared with the other criteria. Results indicate that buckling design based on energy barrier approach can be used as an efficient way in the lightweight design of thin-shell structures.