bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of Low-Re Turbulence Models and Analysis of Turbulent Flow in Porous Media Consisting of Square Cylinders With Different Diameter Ratios
Authors: Alonzo-Garcia Alejandro , Mendoza-Rosas Ana T. , Díaz-Viera Martín A. , Martínez-Delgadillo Sergio A. , Martínez-Mendoza Edgar G. 
Published: August 2020

Abstract
This paper presents a comparative study of volume average predictions between low-Reynolds-number (LRN) turbulence models: Abe–Kondoh–Nagano (AKN), Lam–Bremhorst, Yang–Shih, standard k–ϵ, and k–ω. A porous medium, which represents conditions in which the flow path changes rapidly, was defined as an infinite array of square cylinders. In addition, to explore the effect of particle size on the rapid expansion and contraction of the flow paths, the diameter ratio (DR) of the square cylinders was systematically varied from 0.2 to 0.8. This generalization revealed new insights into the flow. The Reynolds number (ReD) covered a turbulent range of 500 to 500 × 103, and the porosity ϕ was varied from 0.27 to 0.8. The correlations of the turbulent kinetic energy (k), its dissipation rate (ε), and macroscopic pressure gradient as a function of ϕ, which are useful in macroscopic turbulence modeling, are presented. The results show that the AKN model yields better predictions of the volume-averaged flow parameters because it is better suited to reproduce recirculation zones. For all the DRs, at high ϕ, the distances between walls are high, and the interstitial velocities are low. Consequently, wake flows are produced, and energy losses by friction are moderate. As the flow becomes increasingly bound, the wakes are suppressed and disrupted, and k and ε increase owing to shear layer interactions and frictional forces. Distinctive low-velocity recirculation patterns appear inside pores depending on DR.
Passive Reduction of Leakage by Transverse Jet
Authors: Wasilczuk Filip , Flaszyński Paweł , Kaczyński Piotr , Szwaba Ryszard , Doerffer Piotr , Marugi Krzysztof 
Published: August 2020

Abstract
This article presents investigations of mass flow reduction in a gap above a fin by the air curtain technique. The proposed method uses slots in the fin to generate a bypass flow and to create a fluidic barrier in the gap above the fin. Both numerical and experimental researches were conducted and the air curtain proved to be effective, showing the mass flow reduction up to about 20%. The comparison of numerical simulations and experimental data showed good agreement, and the flow structure details were analyzed based on the numerical results. The analysis shows that the blown air in the gap leads to creation of streamwise vortices. They enforce crosswise nonuniformity of the flow velocity in the gap and downstream, what finally influences on higher dissipation effects and mass flow reduction in the gap.
Droplet Impingement on a Surface at Low Reynolds Numbers
Authors: Seksinsky Drue , Marshall Jeffrey S. 
Published: August 2020

AbstractA computational study was conducted of axisymmetric droplet impingement on a flat surface at low droplet Reynolds numbers. The study was motivated by the problem of deposition of melted volcanic ash particles within aircraft gas turbine engines. The computations were performed using the combined level-set volume-of-fluid method for droplet Reynolds numbers between 0.05 and 10. The computational predictions were validated using existing experimental data. The computations indicate that contact radius increases over short time in proportion to the square root of time, in agreement with short-time analytical predictions. Typical assumptions made in development of approximate droplet impingement models were evaluated for low Reynolds number droplet impingement. The droplet shape was well approximated by a truncated spherical cap through most of the impingement process. The surface area over which the droplet spreads increases with increase in Reynolds number. The axial velocity component was found to be approximately independent of radial location over most of the droplet, and the radial velocity component was observed to vary log-normally in the axial coordinate and linearly in radius. The energy dissipation rate was distributed throughout the droplet for low Reynolds numbers cases, but became increasingly localized near the contact line as the Reynolds number increased past unity.
Discrepancy in the Aerodynamic Property and Flowfield of a Symmetric Airfoil Produced by the Stationary and Moving Ground Effect
Authors: Tremblay-Dionne V. , Lee T. 
Published: August 2020

AbstractThe discrepancy in the aerodynamic property and flowfield of a symmetric airfoil produced by the stationary and moving ground effect was quantified through surface pressure and particle-image-velocimetry measurements. The results show that the stationary ground effect produced a higher lift than the moving ground due to the flow passage restriction caused by the longitudinal boundary layer developed on its ground surface. In close ground proximity, the formation of a ground vortex beneath the airfoil's leading-edge region speeded up the flow, leading to a lower lift than its moving-ground counterpart. For the moving ground, the ground vortex was absent. In close ground proximity, the moving ground effect generated a larger wake and drag than the stationary ground effect.
Multi-Objective Optimization of a High Specific Speed Centrifugal Volute Pump Using Three-Dimensional Inverse Design Coupled With Computational Fluid Dynamics Simulations
Authors: Zhang Luying , Davila Gabriel , Zangeneh Mehrdad 
Published: August 2020

AbstractThis paper presents three different multiobjective optimization strategies for a high specific speed centrifugal volute pump design. The objectives of the optimization consist of maximizing the efficiency and minimizing the cavitation while maintaining the Euler head. The first two optimization strategies use a three-dimensional (3D) inverse design method to parametrize the blade geometry. Both meridional shape and 3D blade geometry are changed during the optimization. In the first approach, design of experiment (DOE) method is used and the pump efficiency is obtained from computational fluid dynamics (CFD) simulations, while cavitation is evaluated by using minimum pressure on blade surface predicted by 3D inverse design method. The design matrix is then used to create a surrogate model where optimization is run to find the best tradeoff between cavitation and efficiency. This optimized geometry is manufactured and tested and is found to be 3.9% more efficient than the baseline with reduced cavitation at high flow. In the second approach, only the 3D inverse design method output is used to compute the efficiency and cavitation parameters and this leads to considerable reduction to the computational time. The resulting optimized geometry is found to be similar to the computationally more expensive solution based on 3D CFD results. In order to compare the inverse design based optimization to the conventional optimization, an equivalent optimization is carried out by parametrizing the blade angle and meridional shape.
Compliance of the 24-Hour Movement Guidelines in 9- to 11-Year-Old Children From a Low-Income Town in Chile
Authors: Toledo-Vargas Marcelo , Perez-Contreras Patricio , Chandia-Poblete Damian , Aguilar-Farias Nicolas 
Published: August 2020

Background: The purpose was to determine the proportion of 9- to 11-year-old children meeting the 24-hour movement guidelines (24-HMG) in a low-income town from Chile. Methods: Physical activity, sedentary behavior (recreational screen), and sleep times were measured with both questionnaire and accelerometer in 258 children from third to sixth grade. Meeting the 24-HMG was defined as having ≥60 minutes per day of moderate to vigorous physical activity, ≤2 hour day of screen time, and 9 to 11 hours of sleep per night. Compliance rates were calculated as self-reported 24-HMG, with all estimations based on questionnaires, and mixed 24-HMG, in which physical activity and sleep were determined with an accelerometer and sedentary behavior was determined with a questionnaire. Results: About 198 children (10.1 [0.8] y, range 9–11 y) provided valid data for estimating self-reported 24-HMG, and 141 for mixed 24-HMG. Only 3.2% and 0.7% met the 24-HMG when using the self-reported and mixed methods, respectively. When assessing individual recommendations, 13.1% and 3.7% of the sample were physically active based on the self-report and accelerometer, respectively. About a quarter met the sedentary behavior recommendations, while around 50% met the sleep recommendations with both self-reported and mixed methods. Conclusions: An extremely low percentage of the participants met the 24-HMG. Multicomponent initiatives must be implemented to promote healthy movement behaviors in Chilean children.
The impact of weathering upon the roughness characteristics of a splay of the active fault system responsible for the massive 2016 seismic sequence of the Central Apennines, Italy
Authors: Corradetti Amerigo , Zambrano Miller , Tavani Stefano , Tondi Emanuele , Seers Thomas Daniel 
Published: August 2020

AbstractFault roughness constitutes a key element in the understanding of earthquake nucleation, and surficial asperities on the fault plane play a critical role in slip dynamics and frictional behavior during the seismic cycle. Since it is not generally feasible to recover fault roughness profiles or maps directly at the seismogenic sources, faults at the Earth’s surface are typically used as analogues. However, these analogue fault surfaces are often subjected to weathering and erosion, which in turn, reduces their representativeness as seismogenic faults. Rupture along active faults episodically exposes “fresh” fault planes at the Earth’s surface, which represent the best available targets for the evaluation of fault roughness generated at seismogenic depths.Here we present a study conducted on a splay of the Mt. Vettore fault system in the Central Apennines, Italy, along a vertical transect that includes both a weathered and freshly exposed portion of the fault. The latter was exposed after the dramatic Mw 6.5 shock that hit the area on 30 October 2016. We have produced a highly detailed model (i.e., point cloud) of a section of the fault using structure from motion-multiview stereo photogrammetry to assess its roughness parameters (i.e., the Hurst fractal parameter) and to determine the extent to which these parameters are affected by weathering assuming that they had similar fractal characteristics when reaching the surface.Our results show that weathering can modify the value of the fractal parameters. In particular, by independently analyzing different patches of the fault, we have observed that the smoother and recently exposed portions have an average Hurst exponent of 0.52 while the average Hurst exponent of zones with more prolonged exposure times is 0.64. Accordingly, we conclude that by using high-resolution point clouds, it is possible to recognize patches of faults having a similar intensity of deterioration attributable to weathering.
Using structural and functional MRI as a neuroimaging technique to investigate chronic fatigue syndrome/myalgic encephalopathy: a systematic review
Authors: Almutairi Basim , Langley Christelle , Crawley Esther , Thai Ngoc Jade 
Published: August 2020

ObjectiveThis systematic review aims to synthesise and evaluate structural MRI (sMRI) and functional MRI (fMRI) studies in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME).MethodsWe systematically searched Medline and Ovid and included articles from 1991 (date of Oxford diagnostic criteria for CFS/ME) to first April 2019. Studies were selected by predefined inclusion and exclusion criteria. Two reviewers independently reviewed the titles and abstracts to determine articles for inclusion, full text and quality assessment for risk of bias.ResultssMRI studies report differences in CFS/ME brain anatomy in grey and white matter volume, ventricular enlargement and hyperintensities. Three studies report no neuroanatomical differences between CFS/ME and healthy controls. Task-based fMRI investigated working memory, attention, reward and motivation, sensory information processing and emotional conflict. The most consistent finding was CFS/ME exhibited increased activations and recruited additional brain regions. Tasks with increasing load or complexity produced decreased activation in task-specific brain regions.ConclusionsThere were insufficient data to define a unique neural profile or biomarker of CFS/ME. This may be due to inconsistencies in finding neuroanatomical differences in CFS/ME and the variety of different tasks employed by fMRI studies. But there are also limitations with neuroimaging. All brain region specific volumetric differences in CFS/ME were derived from voxel-based statistics that are biased towards group differences that are highly localised in space. fMRI studies demonstrated both increases and decreases in activation patterns in CFS/ME, this may be related to task demand. However, fMRI signal cannot differentiate between neural excitation and inhibition or function-specific neural processing. Many studies have small sample sizes and did not control for the heterogeneity of this clinical population. We suggest that with robust study design, subgrouping and larger sample sizes, future neuroimaging studies could potentially lead to a breakthrough in our understanding of the disease.
Prevalence of potentially serious alcohol–medication interactions in older adults in a community pharmacy setting: a cross-sectional study
Authors: Holton Alice E , Keeney Cora , Ryan Benedict , Cousins Gráinne 
Published: August 2020

ObjectivePrevious prevalence estimates of POtentially Serious Alcohol–Medication INteractions in Older adults (POSAMINO) are based on in-home inventories of medications; however, this method is associated with under-reporting of medications when compared with dispensing records. This study aims to estimate the prevalence of POSAMINO among community-dwelling older adults using drug dispensing data from the community pharmacy setting.DesignCross-sectional study.SettingIrish Community Pharmacy.Participants1599 consecutive older adults presenting with a prescription to 1 of 120 community pharmacies nationwide; community-dwelling, aged ≥65 years, able to speak and understand English, with no evidence of cognitive impairment. The mean age of sample was 75.5 years (SD 6.5); 55% (n=884) female.Measures38 POSAMINO criteria were identified using participants’ pharmacy dispensing records linked to self-reported alcohol consumption (beverage-specific quantity and frequency measures) over the last 12 months.ResultsThe overall prevalence of POSAMINO in the study population was 28%, with 10% at risk of at least one POSAMINO criteria and 18% at risk of two or more. Exposure to POSAMINO most commonly involved cardiovascular agents (19%) and central nervous system agents (15%). Exposure to a higher number of POSAMINO criteria was associated with younger age (adjusted incident rate ratio (AIRR): 0.97; 95% CI: 0.95 to 0.98), male sex (AIRR: 0.55; 95% CI: 0.45 to 0.67) and a higher number of comorbidities (AIRR: 1.05; 95% CI: 1.01 to 1.13).ConclusionThis study adds to the growing body of evidence, which suggests that older adults are vulnerable to potentially serious alcohol–medication interactions, particularly those involving cardiovascular and central nervous system agents, increasing their risk of orthostatic hypotension, gastrointestinal bleeds and increased sedation. Application of the POSAMINO criteria at the point of prescribing may facilitate the risk stratification of older adults and prioritise alcohol screening and brief alcohol interventions in those at greatest risk of harm.
Understanding parents’ experiences of disease course and influencing factors: a 3-year follow-up qualitative study among parents of children with functional abdominal pain
Authors: Brekke Mette , Brodwall Anne 
Published: August 2020

ObjectiveFunctional abdominal pain is a common symptom in children and adolescents. Three years ago, we investigated the experiences among parents whose children had chronic abdominal pain but no somatic diagnosis. The aim of the present follow-up study was to explore those families’ current situations.DesignInterviews with open questions about the families’ current pain situations were carried out by the first author. Interviews were audio-recorded and transcribed, and subsequently analysed using descriptive content analysis.SettingUrban and rural areas in two municipalities in Southern Norway.ParticipantsParents of children with abdominal pain who had been referred to a local hospital by their general practitioner and had been discharged without a somatic diagnosis. Fifteen parents of 14 children aged 8–17 years who had also been interviewed in 2016.ResultsNine of the children had recovered from their abdominal pain. During the pain period, the parents reported frustration with not having a diagnosis nor a specific treatment for their child’s abdominal pain. The siblings in some families received less attention and were afraid that something serious might happen to their sister or brother. The parents wished that their child’s school cared more about the child when they had weeks of absence. All parents maintained that their child’s pain was physical, although they thought that psychological aspects might have influenced the symptoms. The parents stated that they, as well as their children, needed guidance from professionals to understand the complex pain situation.
Global and regional incidence, mortality and disability-adjusted life-years for Epstein-Barr virus-attributable malignancies, 1990–2017
Authors: Khan Gulfaraz , Fitzmaurice Christina , Naghavi Mohsen , Ahmed Luai A 
Published: August 2020

ObjectiveTo determine the global and regional burden of Epstein-Barr virus (EBV)-attributed malignancies.DesignAn international comparative study based on the Global Burden of Disease (GBD) Study estimates.SettingGlobal population by age, sex, region, demographic index and time.Methods and outcome measuresThe burden of EBV-attributed Burkitt lymphoma (BL), Hodgkin lymphoma (HL), nasopharyngeal carcinoma (NPC) and gastric carcinoma (GC) was estimated in a two-step process. In the first step, the fraction of each malignancy attributable to EBV was estimated based on published studies; this was then applied to the GBD estimates to determine the global and regional incidence, mortality and disability-adjusted life-years (DALYs) for each malignancy by age, sex, geographical region and social demographic index (SDI) from 1990 to 2017.ResultsThe combined global incidence of BL, HL, NPC and GC in 2017 was 1.442 million cases, with over 973 000 deaths. An estimated 265 000 (18%) incident cases and 164 000 (17%) deaths were due to the EBV-attributed fraction. This is an increase of 36% in incidence and 19% in mortality from 1990. In 2017, EBV-attributed malignancies caused 4.604 million DALYs, of which 82% was due to NPC and GC alone. The incidence of both of these malignancies was higher in high and middle-high SDI regions and peaked in adults aged between 50 and 70 years. All four malignancies were more common in males and the highest burden was observed in East Asia.ConclusionsThis study provides comprehensive estimates of the burden of EBV-attributed BL, HL, NPC and GC. The overall burden of EBV-related malignancies is likely to be higher since EBV is aetiologically linked to several other malignancies not included in this analysis. Increasing global population and life expectancy is expected to further raise this burden in the future. The urgency for developing an effective vaccine to prevent these malignancies cannot be overstated.
Mediators of change in healthcare organisations subject to external assessment: a systematic review with narrative synthesis
Authors: Hovlid Einar , Braut Geir Sverre , Hannisdal Einar , Walshe Kieran , Bukve Oddbjørn , Flottorp Signe , Stensland Per , Frich Jan C 
Published: August 2020

ObjectivesExternal inspections are widely used to improve the quality of care. The effects of inspections remain unclear and little is known about how they may work. We conducted a narrative synthesis of research literature to identify mediators of change in healthcare organisations subject to external inspections.MethodsWe performed a literature search (1980–January 2020) to identify empirical studies addressing change in healthcare organisations subject to external inspection. Guided by the Consolidated Framework for Implementation Research, we performed a narrative synthesis to identify mediators of change.ResultsWe included 95 studies. Accreditation was the most frequent type of inspection (n=68), followed by statutory inspections (n=19), and external peer review (n=9). Our findings suggest that the regulatory context in which the inspections take place affect how they are acted on by those being inspected. The way inspections are conducted seem to be critical for how the inspection findings are perceived and followed up. Inspections can engage and involve staff, facilitate leader engagement, improve communication and enable the creation of new networks for reflection on clinical practice. Inspections can contribute to creating an awareness of the inspected organisation’s current practice and performance gaps, and a commitment to change. Moreover, they can contribute to facilitating the planning and implementation of change, as well as self-evaluation and the use of data to evaluate performance.ConclusionsExternal inspections can affect different mediators of organisational change. The way and to what extent they do depend on a range of factors related to the outer setting, the way inspections are conducted and how they are perceived and acted on by the inspected organisation. To improve the quality of care, the organisational change processes need to involve and impact the way care is delivered to the patients.
Palliative care utilisation: family carers’ behaviours and determinants—a qualitative interview study
Authors: Scherrens Anne-Lore , Beernaert Kim , Magerat Laurence , Deliens Luc , Deforche Benedicte , Cohen Joachim 
Published: August 2020

ObjectivesMost research on starting palliative care focuses on the role of healthcare services and professional carers. However, patients and their family carers may also play a role. Especially opportunities for starting palliative care might exist among family carers. This study focused on family carers by identifying their behaviours and underlying determinants that might contribute to starting palliative care.MethodsA qualitative study with 16 family carers of deceased persons who used palliative care was conducted using semistructured, face-to-face interviews. Constant comparison analysis was used to identify groups of behaviours that influenced starting palliative care and related determinants. The behavioural determinants were matched with concepts in existing behavioural theories. A preliminary behavioural model was developed.ResultsMost reported behaviours regarding starting palliative care were related to communicating with the seriously ill person, other family members and professional carers; seeking information and helping the seriously ill person process information from professional carers; and organising and coordinating care. Determinants facilitating and hindering these behaviours included awareness (eg, of poor health), knowledge (eg, concerning palliative care), attitudes (eg, negative connotations of palliative care) and social influences (eg, important others’ opinions about palliative care).ConclusionsThis study identified relevant family carers’ behaviours and related determinants that can contribute to starting palliative care. As these determinants are changeable, the palliative care behavioural model that resulted from this study can serve as a basis for the development of behavioural interventions aiming at supporting family carers in performing behaviours that might contribute to starting palliative care.