bluuebunny/crossref_metadata_2025_split huggingface dataset:
Large-Eddy Simulation of Variable Speed Power Turbine Cascade With Inflow Turbulence
Authors: Miki Kenji , Ameri Ali 
Published: March 2021

Abstract
Numerical results are presented from the National Aeronautics and Space Administration (NASA) Glenn Research Center's in-house turbomachinery code Glenn-HT applied to the variable-speed power turbine (VSPT) experiment at the NASA Transonic Turbine Blade Cascade Facility. The main goal of this paper is to implement a digital filtering method to generate turbulence upstream and a subgrid model (localized dynamic k-equation model (LDKM)) in the framework of large-eddy simulation (LES) in order to investigate the effect of inflow turbulence on the transition seen in the VSPT experimental data at the cruise condition (incidence angle of 40 deg and Tu = 0.5%, 5%, 10%, and 15%). Although the boundary layer on the suction side and pressure side of the blades is initially laminar due to favorable pressure gradient, the laminar flow can transition to turbulent flow past a separation zone on the suction side or by natural or bypass transition. This process determines the total pressure losses in the wake. Therefore, it is desirable to develop a reliable prediction tool to accurately capture the transition mechanism in blade rows operated under the conditions of low Reynolds number and at a variety of freestream turbulence conditions. Our numerical studies reveal that the location of separation is rather insensitive to the level of Tu; however, the effect of increasing Tu seems to be in reducing the size and ultimately suppressing the separation bubble. In addition, we performed spectral analysis to identify the peak frequencies in the region where the separation bubble is formed, which provides valuable insights into the transition/separation mechanism.
Aerodynamic Effects of an Incoming Vortex on Turbines With Different Tip Geometries
Authors: Zhou Kai , Zhou Chao 
Published: March 2021

Abstract
Experimental and numerical methods were used to investigate the aerodynamic effects of a near-casing streamwise incoming vortex flow on the tip leakage flow of different tip geometries in an unshrouded high-pressure turbine. A flat tip, a cavity tip, and a suction side winglet tip were investigated with the quasi-steady method first. A swirl generator was used to produce the incoming vortex in a linear cascade. In the flat tip case, the incoming vortex interacts with the tip leakage flow and the two vortices gradually mix together. The tip leakage loss is reduced due to the streamwise momentum supplement within the tip leakage vortex core. For the cavity tip, the tip leakage vortex appears at a location relatively downstream in the blade passage compared with the flat tip and no evident vortex interaction is observed. The incoming vortex causes extra viscous dissipation within the blade passage and increases the aerodynamic loss for the cavity tip. For the winglet tip, the extension of the suction side winglet tends to push the incoming vortex and the tip leakage vortex move and mix together, thus reducing the loss. Then, the effects of periodic unsteady vortex transportations were investigated by conducting unsteady Reynolds-Averaged Navier–Stokes (URANS) simulations. The incoming vortex is stretched as it transports downstream. The unsteady incoming vortex is easier to interact with the tip leakage vortex for the winglet tip. As a result, the winglet tip is the most efficient tip design with unsteady incoming flow among the three tips and achieves a 3.7% reduction of mixed-out loss coefficient compared with the flat tip, larger than 2.8% reduction in the uniform inlet condition. The detailed loss mechanism is discussed in this paper.
Assessment of MULTALL as Computational Fluid Dynamics Code for the Analysis of Tube-Axial Fans
Authors: Danieli Piero , Masi Massimo , Delibra Giovanni , Corsini Alessandro , Lazzaretto Andrea 
Published: March 2021

Abstract
This work deals with the application of the open-source computational fluid dynamics (CFD) code MULTALL to the analysis of tube-axial fans. The code has been widely validated in the literature for high-speed turbomachine flows but not applied yet to low-speed tutbomachines. The aim of this work is to assess the degree of reliability of MULTALL as a tool for simulating the internal flow in industrial axial-flow fan rotors. To this end, the predictions of the steady-state air-flow field in the annular sector of a 315 mm tube-axial fan obtained by MULTALL 18.3 are compared with those obtained by two state-of-the-art CFD codes and experimental data of the global aerodynamic performance of the fan and the pitch-wise averaged velocity distribution downstream of the rotor. All the steady-state Reynolds-averaged Navier–Stokes (RANS) calculations were performed on either fully structured hexahedron or hexa-dominant grids using classical formulations of algebraic turbulence models. The pressure curve and the trend of the aeraulic efficiency in the stable operation range of the fan predicted by MULTALL show very good agreement with both the experimental data and the other CFD results. Although the estimation of the fan efficiency predicted by MULTALL can be noticeably improved by the more sophisticated state-of-the-art CFD codes, the analysis of the velocity distribution at the rotor exit supports the use of MULTALL as a reliable CFD analysis tool for designers of low-speed axial fans.
Toward Sub-Surface Pore Prediction Capabilities for Laser Powder Bed Fusion Using Data Science
Authors: Ertay Deniz Sera , Kamyab Shima , Vlasea Mihaela , Azimifar Zohreh , Ma Thanh , Rogalsky Allan D. , Fieguth Paul 
Published: March 2021

Abstract
Achieving defect-free parts is traditionally challenging in laser powder bed fusion (LPBF). The mechanical properties of additively manufactured parts are highly affected by their density; as such, research in defect detection and pore prediction has gained significant interest. The process parameters, the powder characteristics, and the process environment conditions play an important role in defect occurrence. Moreover, the laser scan path affects density, especially at scan path discontinuities. In this work, the complex interaction between the process parameters and the scan path on the occurrence of subsurface pores is investigated. In the data preparation step, a synthetic data set is generated to model the melt pool morphology along the scan path. A secondary data set containing the pore space of the resulting parts is obtained via X-ray computed tomography (CT) and is registered with the synthetic data set. Machine learning models, namely, a Conditional Variational AutoEncoder (CVAE) and a Convolutional Neural Network (CNN), are then trained based on the input features to predict pore occurrence. The performance evaluation of both CNN and CVAE models on synthetic data indicates that the scan path and process parameters can be utilized in predicting pore locations. Quantitative results show that employing offline CT images a priori in training the CVAE, without the need to have CT information in the test phase, leads the CVAE model to superior performance over the CNN.
An Investigation into the Texture Transfer in the Process of Lubricated Skin Pass Rolling
Authors: Wu Chuhan , Zhang Liangchi , Qu Peilei , Li Shanqing , Jiang Zhenglian , Li Wei 
Published: March 2021

Abstract
This article investigates the surface texture transfer mechanisms in lubricated skin pass rolling of metal strips with three-dimensional rough surfaces of both regular patterns and random surface asperity distributions. Two important steps have been completed. The first is the successful establishment of an efficient numerical method for predicting the 3D texture transfer. It was identified that the new method can be used reliably with the key complex factors coupled in skin pass rolling, such as the effects of lubricant and surface roughness. The second is the exploration of the texture transfer mechanisms with the aid of this new method. In addition, the effects of hydrodynamic pressure on the texture transfer efficiency were comprehensively investigated by a dynamic explicit finite element analysis. It was found that lubrication plays a critical role in determining the surface texture transfer. The texture transfer ratio decreases with increasing the lubricant viscosity. A larger pressure coefficient brings about a lower texture transfer ratio, but a larger reduction ratio leads to a greater texture transfer.
The Recombinant Luciferase of the Fungus Neonothopanus nambi: Obtaining and Properties
Authors: Gorokhovatsky A. Yu. , Chepurnykh T. V. , Shcheglov A. S. , Mokrushina Yu. A. , Baranova M. N. , Goncharuk S. A. , Purtov K. V. , Petushkov V. N. , Rodionova N. S. , Yampolsky I. V. 
Published: March 2021

Abstract
A key component of the recently described bioluminescent system of higher fungi is luciferase, a new class of proteins. The properties of fungal luciferase and their relationship with its structure are interesting both for improving autoluminescent systems already created on its basis and for creating new ones. Therefore, it is extremely important to understand the spatial structure of this protein. We have performed heterologous expression and purification of Neonothopanus nambi luciferase, obtained a protein suitable for subsequent crystallization, and also determined some biochemical properties of the recombinant luciferase.
Three-year OCT predictive factors of disease recurrence in eyes with successfully treated myopic choroidal neovascularisation
Authors: Borrelli Enrico , Battista Marco , Vella Giovanna , Sacconi Riccardo , Querques Lea , Grosso Domenico , Bandello Francesco , Querques Giuseppe 
Published: March 2021

PurposeTo assess the relationship of demographics, clinical characteristics and structural optical coherence tomography (OCT) findings to disease recurrence in a cohort of patients with newly diagnosed myopic choroidal neovascularisation (CNV)MethodsIn this retrospective, longitudinal study, a total of 64 participants (64 eyes) with successfully treated myopic CNV had obtained resolution of exudation after treatment (study baseline) and with 3 years of regular follow-ups. Several baseline OCT qualitative features and quantitative measurements were assessed at baseline and included in the analysis. Main outcome measures included incidence of disease recurrence and HR for demographics, clinical characteristics and OCT risk factors.ResultsAt month 36, 40 eyes (62.5%) developed disease recurrence (active CNV). Multivariate linear regression analysis revealed that final visual acuity (dependent variable) was associated with visual acuity at the first visit after complete resolution of exudation (p<0.0001), baseline size of patchy atrophy (p=0.010), baseline subfoveal choroidal thickness (p=0.008), baseline maximum CNV height and width (p=0.011 and p=0.003) and recurrence of CNV exudation (p=0.007). The following factors were associated with an increased risk of disease recurrence: size of patchy atrophy had an HR of 1.14 (95% CI 1.01 to 1.29; p=0.036); maximum CNV width had an HR of 1.02 (95% CI 1.01 to 1.04; p<0.0001).ConclusionWe identified OCT risk factors for the disease recurrence in eyes with successfully treated myopic CNV. Assuming that disease recurrence is a sight-threatening event, our findings may help in the identification of high-risk patients and eventually ameliorate their outcome.
Years of potential life lost in pre-diabetes and diabetes mellitus: data from a 40-year follow-up of the Israel study on Glucose intolerance, Obesity and Hypertension
Authors: Rapoport Micha , Chetrit Angela , Cantrell Dror , Novikov Ilya , Roth Jesse , Dankner Rachel 
Published: March 2021

IntroductionWe examined years of potential life lost (YPLL) associated with pre-diabetes as compared with either normoglycemia or diabetes, using data of the Israel cohort of Glucose intolerance, Obesity and Hypertension 40-year follow-up.Research design and methodsMen and women (N=2844, mean age 52.0±8.2 years) who underwent oral glucose tolerance test and anthropometric measurements, during 1976–1982, were followed for mortality until May 2019. Multiple imputation procedures for missing mortality dates and multivariable regression mixed models were applied.ResultsAt baseline, 35.8%, 48.8% and 15.4% individuals were found with normoglycemia, pre-diabetes, and diabetes, respectively. The average difference in YPLL associated with pre-diabetes as compared with normoglycemia was 4.3 years (95% CI 3.3 to 5.2; p<0.001). YPLL were 1 year higher in women with pre-diabetes than in men with pre-diabetes. These differences persisted mainly in individuals younger than 60 years, and those with body mass index (BMI) <25 kg/m2, at baseline. Adjusting for age, sex, country of origin, smoking status, BMI, and blood pressure, the average difference in YPLL associated with pre-diabetes as compared with normoglycemia was 2.0 years (95% CI 1.2 to 2.8; p<0.001). Significant reductions of 5.9 years (95% CI 4.8 to 7.0) on average were observed for diabetes as compared with pre-diabetes and 7.9 years (95% CI 6.7 to 9.1) as compared with individuals with normoglycemia.ConclusionsThis study reveals that life expectancy of middle-aged individuals with pre-diabetes is shorter than of normoglycemic ones. These findings are especially relevant in view of the rising worldwide prevalence of pre-diabetes within younger age groups and underscore the crucial importance of interventions by either lifestyle modification or drug therapy capable of delaying progression from pre-diabetes to diabetes to reduce the YPLL in this high-risk group.
Beyond deaths per capita: comparative COVID-19 mortality indicators
Authors: Heuveline Patrick , Tzen Michael 
Published: March 2021

ObjectivesFollowing well-established practices in demography, this article discusses several measures based on the number of COVID-19 deaths to facilitate comparisons over time and across populations.SettingsNational populations in 186 United Nations countries and territories and populations in first-level subnational administrative entities in Brazil, China, Italy, Mexico, Peru, Spain and the USA.ParticipantsNone (death statistics only).Primary and secondary outcome measuresAn unstandardised occurrence/exposure rate comparable to the Crude Death Rate; an indirectly age-and-sex standardised rate that can be derived even when the breakdown of COVID-19 deaths by age and sex required for direct standardisation is unavailable; the reduction in life expectancy at birth corresponding to the 2020 number of COVID-19 deaths.ResultsTo date, the highest unstandardised rate has been in New York, at its peak exceeding the state 2017 crude death rate. Populations compare differently after standardisation: while parts of Italy, Spain and the USA have the highest unstandardised rates, parts of Mexico and Peru have the highest standardised rates. For several populations with the necessary data by age and sex for direct standardisation, we show that direct and indirect standardisation yield similar results. US life expectancy is estimated to have declined this year by more than a year (−1.26 years), far more than during the worst year of the HIV epidemic, or the worst 3 years of the opioid crisis, and to reach its lowest level since 2008. Substantially larger reductions, exceeding 2 years, are estimated for Panama, Peru, and parts of Italy, Spain, the USA and especially, Mexico.ConclusionsWith lesser demand on data than direct standardisation, indirect standardisation is a valid alternative to adjust international comparisons for differences in population distribution by sex and age-groups. A number of populations have experienced reductions in 2020 life expectancies that are substantial by recent historical standards.
Scheduled Prophylactic 6-Hourly IV AcetaminopheN to Prevent Postoperative Delirium in Older CaRdiac SurgicAl Patients (PANDORA): protocol for a multicentre randomised controlled trial
Authors: Khera Tanvi , Mathur Pooja A , Banner-Goodspeed Valerie M , Narayanan Shilpa , Mcgourty Marie , Kelly Lauren , Palihnich Kerry , Novack Lena , Davis Roger , Talmor Daniel , Marcantonio Edward R , Subramaniam Balachundhar 
Published: March 2021

IntroductionPostoperative delirium is common among older cardiac surgery patients. Often difficult to predict and address prophylactically, delirium complicates the postoperative course by increasing morbidity and mortality as well as prolonging both hospital and intensive care unit (ICU) lengths of stay. Based on our pilot trial, we intend to study the effect of scheduled 6-hourly acetaminophen administration for 48 hours post-cardiac surgery with cardiopulmonary bypass (CPB) on the incidence of in-hospital delirium and long-term neurocognitive outcomes. Additionally, effect on duration and severity of delirium, rescue analgesic consumption, acute and chronic pain scores and lengths of hospital and ICU stay will also be explored.Methods and analysisThis multicentre, randomised, placebo-controlled, quadruple-blinded trial will include 900 older (>60 years) cardiac surgical patients requiring CPB. Patients meeting the inclusion criteria and not meeting any exclusion criteria will be enrolled at seven centres across the USA with Beth Israel Deaconess Medical Center (BIDMC), Boston, as the central coordinating centre. Additional sites may be included to broaden or speed accrual. The primary outcome measure is the incidence of in-hospital delirium till day 30. Secondary outcomes include the duration and severity of in-hospital delirium, hospital and ICU lengths of stay, postoperative pain scores, postoperative rescue analgesic consumption, postoperative cognitive function and chronic sternal pain. Creation of a biorepository and the use of intraoperative-blinded electroencephalogram (EEG) and cerebral oximetry data will support exploratory endpoints to determine mechanistic predictors of postoperative delirium.Ethics and disseminationThis trial is approved and centrally facilitated by the Institutional Review Board at BIDMC. An independent Data Safety and Monitoring Board is responsible for maintaining safety oversight. Protocol # 2019 P00075, V.1.4 (dated 20 October 2020).Trial registration numberNCT04093219.
Association between urbanisation and the risk of hyperuricaemia among Chinese adults: a cross-sectional study from the China Health and Nutrition Survey (CHNS)
Authors: Yu Xixi , Zhu Cheng , Zhang Han , Shen Ziyan , Chen Jing , Gu Yulu , Lv Shiqi , Zhang Di , Wang Yulin , Ding Xiaoqiang , Zhang Xiaoyan 
Published: March 2021

ObjectiveTo explore the association between urbanicity and hyperuricaemia (HUA) and whether urbanicity is an independent risk factor for HUA in Chinese adults.DesignData analysis from a cross-sectional survey.Setting and participants8579 subjects aged 18 years or older were enrolled in the study from the 2009 wave of the China Health and Nutrition Survey to analyse the association between urbanicity and HUA. We divided them into three categories according to urbanisation index (low, medium and highly urbanised groups).Main outcome measuresHUA was defined as serum uric acid ≥7 mg/dL in men and ≥6 mg/dL in women.ResultsThe prevalence of HUA in low, medium and highly urbanised groups was 12.2%, 14.6% and 19.8%, respectively. The independent factors influencing serum uric acid included age, gender, hypertension, diabetes, chronic kidney disease, drinking, obesity and community-level urbanisation index (β=0.016, p<0.001). The risk of HUA in the highly urbanised group was significantly higher than that of the low urbanised group (OR 1.771, 95% CI 1.545 to 2.029, p<0.001), even after adjusting for other covariates (OR 1.661, 95% CI 1.246 to 2.212, p=0.001). In a subgroup analysis, we found that age, gender, comorbidity (such as hypertension, diabetes, obesity and chronic kidney disease) and physical activity affected the association between urbanisation and the risk of HUA.ConclusionsOur findings suggest that living in highly urbanised areas is linked with higher risk of HUA independent of cardiometabolic and health-related behavioural risk factors, which have been shown to increase along with urbanisation.
Is the public supportive and willing to pay for a national assistive reproductive therapies programme? Results from a multicountry survey
Authors: Skedgel Chris , Ralphs Eleanor , Finn Elaine , Whitty Jennifer A , Markert Marie , Samuelsen Carl 
Published: March 2021

ObjectivesTo understand attitudes towards infertility and willingness to pay (WTP) towards a publicly funded national assistive reproductive therapies (ART) programme.DesignAttitudes survey with dichotomous and open-ended WTP questions.SettingOnline survey administered in the USA, UK, Spain, Norway, Sweden, Finland, Denmark and China.Participants7945 respondents, analysed by country. Nordic respondents were pooled into a regionally representative sample.Primary and secondary outcome measuresPrimary outcome measures were proportion of sample agreeing with different infertility-related and ART-related value statements and supporting a monthly contribution to fund a national ART programme, expressed in local currency. Secondary outcome measure was maximum WTP.ResultsAcross the nationally representative samples, 75.5% of all respondents agreed with infertility as a medical condition and 82.3% and 83.7% with ART eligibility for anyone who has difficulty having a baby or a medical problem preventing them from having a baby, respectively. 56.4% of respondents supported a defined monthly contribution and 73.9% supported at least some additional contribution to fund a national ART programme. Overall, converting to euros, median maximum WTP was €3.00 and mean was €15.47 (95% CI 14.23 to 16.72) per month. Maximum WTP was highest in China and the USA and lowest in the European samples.ConclusionsThis large, multicountry survey extends our understanding of public attitudes towards infertility and fertility treatment beyond Europe. It finds evidence that a majority of the public in all sampled countries/regions views infertility as a treatable medical condition and supports the idea that all infertile individuals should have access to treatments that improve the chance of conception. There was also strong agreement with the idea that the desire for children is a basic human need. WTP questions showed that a majority of respondents supported a monthly contribution to fund a national ART programme, although there is some evidence of an acquiescence bias that may overstate support among specific samples.