bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Virtual Work Model for the Design and Parameter Identification of Cylindrical Pressure-Driven Soft Actuators
Authors: Lamping Frederik , de Payrebrune Kristin M. 
Published: October 2021

Abstract
In this paper, we derive a model based on the principle of virtual work to describe the deformations of cylindrical pressure-driven soft actuators with four types of fiber reinforcement and with externally applied forces. Such cylindrical actuators are often used as the basis for multi-chamber soft robotic systems, for example, bending actuators. In the virtual work model, each type of reinforcement leads to particular geometric constraints; the energy of the stretched material is determined by the Yeoh material model. Finally, the stretch of the actuator is solved numerically by a minimization problem. The virtual work model yielded only little deviations of the predicted stretch relative to finite element simulations in abaqus. The key contribution of the virtual work model is improved parameter identification for the modeling of cylindrical soft actuators, as it illustrates the possibility to distinguish between material-dependent behavior and geometry-dependent behavior of these actuators. Also, the virtual work model is applicable in the design process of the investigated actuators. We demonstrate that an optimization of the actuator’s inner and outer radii and of its fiber angle, respectively, is possible and we derive design rules including criteria for the choice of fiber reinforcement.
A Novel Scientific Approach to Compare the Effectiveness of Well Stimulation and Artificial Lifting
Authors: Abbaspour Mitra , Mahdiyar Hojjat , Kazemzadeh Yousef , Eskroochi Mehdi , Nasrabadi Mohsen 
Published: October 2021

Abstract
Production rate decline is one of the most common challenges in production engineering. Obviously, the first step to overcome this challenge is to understand its main reason. In this article, a new approach is developed which can be used to compare the effectiveness of artificial lifting and well stimulation. The method is based on a couple of charts that summarize the results of integrated simulation of formation and well-column. In the first graph, called the flow productivity index curve, the production rate is drawn as a function of the productivity index. Some important points are also specified on this diagram which are current state, production rate at maximum possible productivity index, and production rate when the well is equipped with a pump or gas lifting. In the second graph, derivatives of the production rate of different wells are drawn as a function of the productivity index. The analysis of three actual wells with conventional inflow performance relationship-tubing performance relationship (IPR-TPR) curves and also our suggested curves are discussed in this paper. It is seen that the introduced approach can be used as a powerful tool to predict the effectiveness of well stimulation and artificial lifting and make a clear comparison between them.
Three-Dimensional Simulation Analysis of the Effect of Hydrous Ethanol and Exhaust Gas Recirculation on Gasoline Direct Injection Engine Combustion and Emissions
Authors: Shi Xiuyong , Jiang Yixiao , Wang Qiwei , Qian Weiwei , Huang Rong , Ni Jimin 
Published: October 2021

Abstract
To analyze the influence of hydrous ethanol on the performance of the direct-injection engine, the three-dimensional simulation is carried out by using converge software coupled with the combustion mechanism of hydrous ethanol gasoline and the soot model. The combustion and soot generation characteristics of a direct-injection gasoline engine burning hydrous ethanol gasoline using exhaust gas recirculation (EGR) technology are investigated. It is found that the increase of the blending ratio of the hydrous ethanol can accelerate the flame propagation speed, shorten the combustion duration, and improve the combustion isovolumetric. The nucleation and growth of soot are jointly controlled by polycyclic aromatic hydrocarbons (PAHs) and the small molecular components such as C2H2. The oxygen content properties and high reactive OH of the hydrous ethanol-containing gasoline inhibit soot formation. Compared with pure gasoline, the carbon soot precursor mass is reduced by 60%, 54.5%, 73.3%, and 52.4% for 20% anhydrous ethanol blended with gasoline, A1, A2, A3, and A4, respectively, and the carbon soot mass is reduced by 63.6% and the carbon soot volume density is reduced by 40%. The introduction of EGR exhaust reduces the burning rate and leads to an increase in the production of carbon monoxide, hydrocarbon, and soot. However, the combination of EGR with hydrous ethanol gasoline can significantly improve the engine combustion environment and significantly reduce soot and PAHs concentrations. The impact of EGR also includes the ability to reduce combustion chamber temperatures and reduce NOx emissions from hydrous ethanol gasoline by 75%.
A Numerical Study of the Hydrodynamics of an Offshore Fish Farm Using REEF3D
Authors: Wang Gang , Martin Tobias , Huang Liuyi , Bihs Hans 
Published: October 2021

Abstract
In this article, the hydrodynamics of and nonlinear interaction between the large offshore fish farm “ShenLan 1” and regular waves are investigated using the open-source computational fluid dynamics (CFD) toolbox REEF3D. The framework consists of a rigid body dynamics solver for the frame structure coupled to a fluid solver including the shielding effects of the nets. The solver and grid independence are validated using a 2D numerical wave tank, a free decay test, and a study of the wave loads on a rigid net panel. Then, the effects of regular wave parameters, the thickness of the vertical outer columns of the structure, and the variations of the aspect ratios on the loads, responses, and maximum mooring tension forces are studied. It is concluded that the response motion is sensitive to the wave period rather than the wave height due to the longer duration of unidirectional wave loads acting on the frame. The frequent events of partial submersions and wave overtopping in rather steep waves are confirmed through the capturing of the free surface. The net system accounts for about 30% of the total drag but does not influence the structural response to a larger extend. The effect of the aspect ratio on the hydrodynamics is more distinct than that of the frame thickness. As a result of the study, the first step toward a systemic evaluation of the importance of different structural parts of an offshore fish cage for the expected responses is provided.
Fretting Wear Behavior of Micro-Arc Oxidation Coating Fabricated on AZ91 Magnesium Alloy
Authors: Zhang Fei , Yin Meigui , Li Qiang 
Published: October 2021

Abstract
In this study, the effect mechanisms between the fretting wear behavior and properties of micro-arc oxidation (MAO) coatings fabricated by different anodic voltages (AVs) on AZ91 magnesium alloy were investigated. The microstructure and macroscopic mechanical properties of the MAO coatings were analyzed by various characterization means. The evolution rule of fretting wear behaviors was carried out through sliding fretting wear experiment under different test parameters. The results showed that the increase in AV increased the MAO coating surface roughness and elastic modulus. The fretting wear resistance of magnesium alloy also enhanced after treatment by MAO, and the improvement effect was positively correlated to AV. Further studies revealed that the wear mechanisms of AZ91 magnesium alloy were oxidation wear and fatigue spalling, and that of MAO coating was mixed abrasive wear and fatigue spalling.
Nonlinear Behavior of Helmholtz Resonator With a Compliant Wall for Low-Frequency, Broadband Noise Control
Authors: Pishvar Maya , Harne Ryan L. 
Published: October 2021

Abstract
Low-frequency sound attenuation is often pursued using Helmholtz resonators (HRs). The introduction of a compliant wall around the acoustic cavity results in a two degrees-of-freedom (2DOF) system capable of more broadband sound absorption. In this study, we report the amplitude-dependent dynamic response of a compliant-walled HR and investigate the effectiveness of wall compliance to improve the absorption of sound in linear and nonlinear regimes. The acoustic-structure interactions between the conventional HR and the compliant wall result in non-intuitive responses when acted on by nonlinear amplitudes of excitation pressure. This paper formulates and studies a reduced order model to characterize the nonlinear dynamic response of the 2DOF HR with a compliant wall compared to that of a conventional rigid HR. Validated by experimental evidence, the modeling framework facilitates an investigation of strategies to achieve broadband sound attenuation, including by selection of wall material, wall thickness, geometry of the HR, and other parameters readily tuned by system design. The results open up new avenues for the development of efficient acoustic resonators exploiting the deflection of a compliant wall for suppression of extreme noise amplitudes.
Short-lived intra-oceanic arc-trench system in the North Qaidam belt (NW China) reveals complex evolution of the Proto-Tethyan Ocean
Authors: Fu Changlei , Yan Zhen , Aitchison Jonathan C. , Xiao Wenjiao , Buckman Solomon , Wang Bingzhang , Zhai Qingguo , Cao Bo 
Published: October 2021

Abstract
Recognition of any intra-oceanic arc-trench system (IOAS) could provide invaluable information on the tectonic framework and geodynamic evolution of the vanished ocean basin. The Tanjianshan Complex and mafic-ultramafic rocks along the North Qaidam ultra-high pressure metamorphic belt in NW China record the subduction process of the Proto-Tethyan Ocean. Four lithotectonic units, including island arc, ophiolite, forearc basin, and accretionary complex, are recognized based on detailed field investigation. They rest on the northern margin of the Qaidam block and occur as allochthons in fault contact with underlying high-grade metamorphic rocks. The ophiolite unit mainly consists of ultramafic rocks, 527–506 Ma gabbro, 515–506 Ma plagiogranite, dolerite, and massive lava. High-Cr spinels in serpentinite, dolerite with forearc basalt affinity, and boninitic lava collectively indicate a forearc setting. The accretionary complex, exposed to the south of the ophiolite complex and island arc, is highly disrupted and contains repeated slices of basalt, 495–486 Ma tuff, chert, limestone, and mélange. Tuffs with positive zircon εHf(t) values indicate derivation from a nearby juvenile island arc. These lithotectonic units, as well as the back-arc basin, are interpreted to constitute a Cambrian IOAS that formed during the northward subduction of the Proto-Tethyan Ocean. Combined with regional geology, we propose a new geodynamic model involving short-lived Mariana-type subduction and prolonged Andean-type subduction to account for the complex evolution of the Proto-Tethyan Ocean. The reconstruction of a relatively complete IOAS from the North Qaidam belt not only reveals a systematic evolution of intra-oceanic subduction but also advances our understanding of the subduction and accretion history of the Proto-Tethyan Ocean.
Impact of intrapartum antibiotics on the infant gastrointestinal microbiome: a narrative review
Authors: Diamond Laura , Wine Rachel , Morris Shaun K 
Published: October 2021

BackgroundThe composition of the infant gastrointestinal (GI) microbiome has been linked to adverse long-term health outcomes and neonatal sepsis. Several factors are known to impact the composition of the microbiome, including mode of delivery, gestational age, feeding method and exposure to antibiotics. The impact of intrapartum antibiotics (IPAs) on the infant microbiome requires further research.ObjectiveWe aimed to evaluate the impact of IPAs on the infant GI microbiome.MethodsWe searched Ovid MEDLINE and Embase Classic+Embase for articles in English reporting on the microbiome of infants exposed to IPAs from the date of inception to 3 January 2021. Primary outcomes included abundance and colonisation ofBifidobacteriumandLactobacillus, as well as alpha and beta diversity.Results30 papers were included in this review. In the first year of life, following exposure to IPAs, 30% (6/20) of infant cohorts displayed significantly reducedBifidobacterium, 89% (17/19) did not display any significant differences inLactobacilluscolonisation, 21% (7/34) displayed significantly reduced alpha diversity and 35% (12/34) displayed alterations in beta diversity. Results were further stratified by delivery, gestational age (preterm or full term) and feeding method.ConclusionsIPAs impact the composition of the infant GI microbiome, resulting in possible reductionsBifidobacteriumand alpha diversity, and possible alterations in beta diversity. Our findings may have implications for maternal and neonatal health, including interventions to prevent reductions in health-promoting bacteria (eg, probiotics) and IPA class selection.
Socioeconomic factors and outcomes from exercise-related sudden cardiac arrest in high school student-athletes in the USA
Authors: Schattenkerk Jared , Kucera Kristen , Peterson Danielle F , Huggins Robert A , Drezner Jonathan A 
Published: October 2021

ObjectiveMinority student-athletes have a lower survival rate from sudden cardiac arrest (SCA) than non-minority student-athletes. This study examined the relationship between high school indicators of socioeconomic status (SES) and survival in student-athletes with exercise-related SCA.MethodsHigh school student-athletes in the USA with exercise-related SCA on school campuses were prospectively identified from 1 July 2014 to 30 June 2018 by the National Center for Catastrophic Sports Injury Research. High school indicators of SES included the following: median household and family income, proportion of students on free/reduced lunch and percent minority students. Resuscitation details included witnessed arrest, presence of an athletic trainer, bystander cardiopulmonary resuscitation and use of an on-site automated external defibrillator (AED). The primary outcome was survival to hospital discharge. Differences in survival were analysed using risk ratios (RR) and univariate general log-binomial regression models.ResultsOf 111 cases identified (mean age 15.8 years, 88% male, 49% white non-Hispanic), 75 (68%) survived. Minority student-athletes had a lower survival rate compared with white non-Hispanic student-athletes (51.1% vs 75.9%; RR 0.67, 95% CI 0.49 to 0.92). A non-significant monotonic increase in survival was observed with increasing median household or family income and with decreasing percent minority students or proportion on free/reduced lunch. The survival rate was 83% if an athletic trainer was on-site at the time of SCA and 85% if an on-site AED was used.ConclusionsMinority student-athletes with exercise-related SCA on high school campuses have lower survival rates than white non-Hispanic athletes, but this difference is not fully explained by SES markers of the school.
Spatial patterns and inequalities in skilled birth attendance and caesarean delivery in sub-Saharan Africa
Authors: Bobo Firew Tekle , Asante Augustine , Woldie Mirkuzie , Dawson Angela , Hayen Andrew 
Published: October 2021

BackgroundImproved access to and quality obstetric care in health facilities reduces maternal and neonatal morbidity and mortality. We examined spatial patterns, within-country wealth-related inequalities and predictors of inequality in skilled birth attendance and caesarean deliveries in sub-Saharan Africa.MethodsWe analysed the most recent Demographic and Health Survey data from 25 sub-Saharan African countries. We used the concentration index to measure within-country wealth-related inequality in skilled birth attendance and caesarean section. We fitted a multilevel Poisson regression model to identify predictors of inequality in having skilled attendant at birth and caesarean section.ResultsThe rate of skilled birth attendance ranged from 24.3% in Chad to 96.7% in South Africa. The overall coverage of caesarean delivery was 5.4% (95% CI 5.2% to 5.6%), ranging from 1.4% in Chad to 24.2% in South Africa. The overall wealth-related absolute inequality in having a skilled attendant at birth was extremely high, with a difference of 46.2 percentage points between the poorest quintile (44.4%) and the richest quintile (90.6%). In 10 out of 25 countries, the caesarean section rate was less than 1% among the poorest quintile, but the rate was more than 15% among the richest quintile in nine countries. Four or more antenatal care contacts, improved maternal education, higher household wealth status and frequently listening to the radio increased the rates of having skilled attendant at birth and caesarean section. Women who reside in rural areas and those who have to travel long distances to access health facilities were less likely to have skilled attendant at birth or caesarean section.ConclusionsThere were significant within-country wealth-related inequalities in having skilled attendant at birth and caesarean delivery. Efforts to improve access to birth at the facility should begin in areas with low coverage and directly consider the needs and experiences of vulnerable populations.
Barriers and facilitators of diabetes management by continuous glucose monitoring systems among adults with type 2 diabetes: a protocol of qualitative systematic review
Authors: Zheng Mingyue , Patel Anamica , Khoja Adeel , Luo Yunting , Lin Wei , He Qian , Zhao Xuan , Wang Juan , Yang Shenqiao , Hu Peng 
Published: October 2021

IntroductionStudies suggest that continuous glucose monitors (CGMs) play an important role in the management of diabetes. Although general acceptance has been reported by patients with type 2 diabetes towards the use of CGMs, potential barriers exist like pain due to sensor insertion, accidental removal of the device or adhesive strip, impacts of daily activities, skin reactions to sensor adhesive, etc. This systematic review of qualitative studies aims to explore the perspectives, experiences and narratives of patients and caregivers about CGM use, and its barriers and facilitators.Methods and analysisThis review will include qualitative studies and cross-sectional and longitudinal cohort studies using open-ended questions, published in English by 30 October 2021. The following electronic databases will be searched: Cochrane Library, PubMed, EMBASE, CINAHL, PsycINFO and Scopus. A search of grey literature will be conducted via an online search of Google Scholar, WorldCat, ClinicalTrials.gov and OpenGrey A combined search strategy using medical subject headings (MeSH), controlled vocabulary and ‘free-text’ terms will be appropriately revised to suit each database. Primary outcomes will include patient and caregiver perspectives on diabetes management regarding glucose control; living with CGM (quality of life, experience of wearing a CGM); psychological aspects (anxiety, depression, emotional burden); barriers (technical issues, financial issues) to use of CGM and thoughts (interpretation, understanding) on the CGM report. A qualitative meta-synthesis will be conducted employing a systematic literature search of existing literature, quality assessment using study-specific tools and an aggregative thematic synthesis by a multidisciplinary team.Ethics and disseminationEthical approval is not required since this is a systematic review. The results will help improve clinical implementation of CGMs on part of both patients and caregivers.PROSPERO registration numberCRD42020152211.
‘Making the most of our situation’: a qualitative study reporting health providers’ perspectives on the challenges of implementing the prevention of mother-to-child transmission of HIV services in Lagos, Nigeria
Authors: Kram Nidal A-Z , Yesufu Victoria , Lott Breanne , Palmer Kelly N B , Balogun Mobolanle , Ehiri John 
Published: October 2021

ObjectivesTo investigate the challenges of, and opportunities for, effective delivery of prevention of mother-to-child transmission (PMTCT) services from the perspectives of primary healthcare providers in Lagos, Nigeria.DesignThis qualitative study consisted of nine focus groups with 59 health providers, analysed thematically.SettingThirty-eight primary health facilities in central and western districts of Lagos, Nigeria.ParticipantsParticipants included nurses, nursing assistants, community health workers, laboratory workers, pharmacists, pharmacy technicians, monitoring and evaluation staff and medical records personnel.ResultsHealth providers’ challenges included frustration with the healthcare system where unmet training needs, lack of basic amenities for effective and safe treatment practices, low wages and inefficient workflow were discussed. Providers discussed patient-level challenges, which included the practice of giving fake contact information for fear of HIV-related stigmatisation, and refusal to accept HIV-positive results and to enrol in care. Providers’ suggestions for addressing PMTCT service delivery challenges included the provision of adequate supplies and training of healthcare workers. To mitigate stigmatisation, participants suggested home-based care, working with traditional birth attendants and religious institutions and designating a HIV health educator for each neighbourhood.ConclusionsFindings illustrate the complex nature of PMTCT service delivery and illuminate issues at the patient and health system levels. These results may be used to inform strategies for addressing identified barriers and to improve the provision of PMTCT services, thus ensuring better outcomes for women and families.
Effectiveness of modified downregulation for women with moderate and severe adenomyosis of the uterus prior to frozen thawed embryo transfer (MODA) study protocol: a pragmatic randomised-controlled trial
Authors: Latif Sania , Wattar Bassel H Al , Balachandren Neerujah , Lukaszewski Tomasz , Saridogan Ertan , Yasmin Ephia , Serhal Paul , Mavrelos Dimitrios 
Published: October 2021

IntroductionAdenomyosis can adversely reduce chances of pregnancy in couples undergoing assisted conception. We aim to evaluate the effect of two different downregulation protocols on the reproductive outcomes in women with moderate and severe adenomyosis undergoing frozen-thawed embryo transfer (FTET).Methods and analysisWe will conduct a two-armed pragmatic randomised clinical trial comparing modified downregulation with gonadotrophin-releasing hormone (GnRH) analogue for 6 weeks to standard downregulation with GnRH analogue for 1 week prior to FTET. Our primary outcome is clinical pregnancy, defined as a viable intrauterine pregnancy confirmed by ultrasound at greater than 6 weeks gestation, with other secondary reproductive, neonatal and safety outcomes. We aim to randomise 162 patients over 3 years to achieve 80% power for detecting a 20% difference in the primary outcome at 5% significance.Ethics and disseminationTo date there is no consensus on the optimal protocol for management of subfertile women with adenomyosis. Modified downregulation could improve the clinical pregnancy rate by reducing the endometrial inflammatory reaction and/or myometrial contractility and their impact on uterine receptivity in women with moderate and severe adenomyosis of the uterus undergoing FTET. The MODA trial is designed to offer pragmatic, real-life evaluation of the optimal protocol for downregulation for this population during assisted conception treatments. Our findings will be published in peer-reviewed journals and presented at national and international scientific meetings and congresses. Ethical approval was granted by the NHS Research Ethics Committees (19/LO/1567).Trial registration numberNCT03946722.