bluuebunny/crossref_metadata_2025_split huggingface dataset:
CFD Simulation of Semi-Submersible Floating Offshore Wind Turbine Under Pitch Decay Motion
Authors: Wang Yu , Chen Hamn-Ching , Vaz Guilherme , Burmester Simon 
Published: December 2019

Abstract
The application of a computational fluid dynamics (CFD) code to simulate the response of a semi-submersible floating wind turbine under pitch decay motion was investigated in this study. Estimation of the natural period, the hydrodynamic damping and the flow characteristics were the main focus of this study. An extensive verification study of the simulation results was conducted to improve the confidence and reliability of the numerical simulation by the estimation of the numerical errors and uncertainties. The time series of pitch motion was plotted against model test data. In addition, the pitch period and hydrodynamic damping were calculated and compared to experimental data. Detailed flow characteristics as vorticity field and hydrodynamic pressure field on the floater surface were illustrated after post processing of the computational data. The results of the flow characteristics suggest that the heave damping plates were a major contributor to the hydrodynamic damping of this floater in pitch decay.
Optimization of the Dynamic Response of Semi-Submersibles: Influence of the Mooring System
Authors: Zhou Shengtao , Lemmer Frank , Yu Wei , Cheng Po Wen , Li Chao , Xiao Yiqing 
Published: December 2019

Abstract
The design and manufacturing cost of substructures is a major component of the total expenditure for a floating wind project. Applying optimization techniques to hull shape designs has become an effective way to reduce the life-cycle cost of a floating wind system. The mooring system is regarded as the component with the highest risk, mainly due to the poor accessibility. This paper extends the previous work by investigating the influences of the mooring design on the optimization process of a semisubmersible substructure. Two optimization loops are set up. In the first loop, only the main dimensions of a semi-submersible platform are parameterized without considering mooring lines (keep a constant mooring design). Nevertheless, the second loop introduces additional variables of the mooring lines. The objective is to minimize the tower-top displacement, fairlead fatigue damage, which are calculated by the in-house nonlinear dynamic simulation code SLOW, and the manufacturing cost of platform and mooring lines. The multi-objective optimization algorithm NSGA-II is employed to search for the optimal designs within the defined design space. The design space and the Pareto fronts are compared between the two optimizations. It is found that, although the mooring design does not have a significant impact on the platform design space, one obtains a different optimal set (Pareto front) if the mooring design and mooring loads are introduced into the platform optimization process. The results of this study are expected to give a better understanding in the relationship between platform and mooring design and serve as a basis for the optimization process of semi-submersible floating wind turbines.
Physical Model Testing of the TetraSpar Demo Floating Wind Turbine Prototype
Authors: Borg Michael , Viselli Anthony , Allen Christopher K. , Fowler Matthew , Sigshøj Christoffer , Grech La Rosa Andrea , Andersen Morten Thøtt , Stiesdal Henrik 
Published: December 2019

Abstract
As part of the process of deploying new floating offshore wind turbines, scale model testing is carried out to de-risk and verify the design of novel foundation concepts. This paper describes the testing of a 1:43 Froude-scaled model of the TetraSpar Demo floating wind turbine prototype that shall be installed at the Metcentre test facility, Norway. The TetraSpar floating foundation concept consists of a floater tetrahedral structure comprising of braces connected together through pinned connections, and a triangular keel structure suspended below the floater by six suspension lines. A description of the experimental setup and program at the Alfond W2 Ocean Engineering Lab at University of Maine is given. The objective of the test campaign was to validate the initial design, and contribute to the development of the final demonstrator design and numerical models. The nonlinear hydrodynamic characteristics of the design are illustrated experimentally and the keel suspension system is shown to satisfy design criteria.
Substructure Flexibility and Member-Level Load Capabilities for Floating Offshore Wind Turbines in OpenFAST
Authors: Jonkman Jason M. , Damiani Rick R. , Branlard Emmanuel S. P. , Hall Matthew , Robertson Amy N. , Hayman Greg J. 
Published: December 2019

Abstract
OpenFAST is an open-source, physics-based engineering tool applicable to the load analysis of land-based and offshore wind turbines, including floating offshore wind turbines. The substructure for a floating wind turbine has historically been modeled in OpenFAST as a rigid body with hydrodynamic loads lumped at a point, which enabled the tool to predict the global response of the floating substructure but not the structural loads within its individual members. This limitation is an impediment to designing floating substructures — especially newer designs that are more streamlined, flexible, and cost-effective. This paper presents the development plan of new capabilities in OpenFAST to model floating substructure flexibility and member-level loads, including the functional requirements and modeling approaches needed to understand and apply them correctly.
Effects of Four Moon Pools on a Floating System Installed With Twin-VAWTs
Authors: Ikoma Tomoki , Nakamura Mitsuru , Moritsu Satsuya , Aida Yasuhiro , Masuda Koichi , Eto Hiroaki 
Published: December 2019

Abstract
This paper describes characteristics of motion responses and tether tensions of a floating structure with four moon pools, on which one or two vertical axis wind turbine models are installed. Effects of several moon pools founded in a floating structure on motion characteristics have been unclear.
In this study, the authors proposed a twin-VAWT installed floating system, which was a pontoon based structure. However four moon pools were set on. The study conducted model experiments in a wave tank using regular waves with 0.6 to 2.0 seconds in wave periods and 0.02 and 0.04 m in wave height. The model had four moon pools and was installed with one or two vertical axis turbine models. From it, gyroscopic moment effects were investigated. Besides, the study performed numerical calculations with the linear potential theory based method which were a Green function method.
As a results, responses of the twin-turbine model are not affected by gyroscopic moment. The study discusses motion responses and tether tensions with nonlinear behaviours from mainly the experimental results. Also the effect of moon pools were investigated from the calculations. From comparisons of motion results on calculation models with same displacement but different draft, the results suggested that not only heave motion but also roll motion could be reduced because of the moon pools if the size of the moon pools were optimized.
Spatiotemporal patterns of distributed slip in southern Owens Valley indicated by deformation of late Pleistocene shorelines, eastern California
Authors: Bacon Steven N. , Bullard Thomas F. , Keen-Zebert Amanda K. , Jayko Angela S. , Decker David L. 
Published: December 2019

AbstractHigh-resolution elevation surveys of deformed late Pleistocene shorelines and new luminescence dating provide improved constraints on spatiotemporal patterns of distributed slip between normal and strike-slip faulting in southern Owens Valley, eastern California. A complex array of five subparallel faults, including the normal Sierra Nevada frontal fault and the oblique-normal Owens Valley fault, collectively form an active pull-apart basin that has developed within a dextral transtensional shear zone. Spatiotemporal patterns of slip are constrained by post–IR-IRSL (post-infrared–infrared stimulated luminescence) dating of a 40.0 ± 5.8 ka highstand beach ridge that is vertically faulted and tilted up to 9.8 ± 1.8 m and an undeformed suite of 11–16 ka beach ridges. The tectono-geomorphic record of deformed beach ridges and alluvial fans indicates that both normal and dextral faulting occurred between the period of ca. 16 and 40 ka, whereas dextral faulting has been the predominant style of slip since ca. 16 ka. A total extension rate of 0.7 ± 0.2 mm/yr resolved in the N72°E direction across all faults in Owens Lake basin is within error of geodetic estimates, suggesting extension has been constant during intervals of 101–104 yr. A new vertical slip rate of 0.13 ± 0.04 m/k.y. on the southern Owens Valley fault from deformed 160 ± 32 ka shoreline features also suggests constant slip for intervals up to 105 yr when compared to paleoseismic vertical slip rates from the same fault segment. This record supports a deformation mechanism characterized by steady slip and long interseismic periods of 8–10 k.y. where the south-central Owens Valley fault and Sierra Nevada frontal fault form a parallel fault system.
Measurement error, microcephaly prevalence and implications for Zika: an analysis of Uruguay perinatal data
Authors: Harville Emily W , Buekens Pierre M , Cafferata Maria Luisa , Gilboa Suzanne , Tomasso Giselle , Tong Van 
Published: December 2019

Background and objectiveThe Zika virus outbreak has drawn attention to microcephaly, whose definition is based on head circumference measuring below a percentile or number of SDs below the mean. The objective of this analysis was to assess how differences in measurement precision might affect prevalence and trends of microcephaly.MethodsData from all births in Uruguay during 2010–2015 were obtained from the Perinatal Information System. The prevalence of births with microcephaly was calculated based on head circumference measurement at birth applying the INTERGROWTH-21st standards for sex and gestational age, and compared by method of ascertaining gestational age.ResultsRounding and digit preference was observed: 74% of head circumference measurements were reported as a whole centimetre value. The prevalence of births varied substantially by the criterion used to define microcephaly (<3 SD, <2 SD, <3rd percentile for gestational age) and could be halved or doubled based on adding or subtracting a half-centimetre from all reported head circumference measurements. If 4 days were added to gestational age calculations, rather than using completed gestational weeks (without days) for gestational age reporting, the prevalence was 1.7–2 times higher.DiscussionRounding in measurement of head circumference and reporting preferences of gestational age may have contributed to a lower prevalence of microcephaly than expected in this population. Differences in head circumference measurement protocols and gestational age dating have the potential to affect the prevalence of babies reported with microcephaly, and this limitation should be acknowledged when interpreting head circumference data collected for surveillance.
Event-based surveillance at health facility and community level in low-income and middle-income countries: a systematic review
Authors: Kuehne Anna , Keating Patrick , Polonsky Jonathan , Haskew Christopher , Schenkel Karl , Le Polain de Waroux Olivier , Ratnayake Ruwan 
Published: December 2019

BackgroundThe International Health Regulations require member states to establish “capacity to detect, assess, notify and report events”. Event-based surveillance (EBS) can contribute to rapid detection of acute public health events. This is particularly relevant in low-income and middle-income countries (LMICs) which may have poor public health infrastructure. To identify best practices, we reviewed the literature on the implementation of EBS in LMICs to describe EBS structures and to evaluate EBS systems.MethodsWe conducted a systematic literature search of six databases to identify articles that evaluated EBS in LMICs and additionally searched for grey literature. We used a framework approach to facilitate qualitative data synthesis and exploration of patterns across and within articles.ResultsWe identified 778 records, of which we included 15 studies concerning 13 different EBS systems. The 13 EBS systems were set up as community-based surveillance, health facility-based surveillance or open surveillance (ie, notification by non-defined individuals and institutions). Four systems were set up in outbreak settings and nine outside outbreaks. All EBS systems were integrated into existing routine surveillance systems and pre-existing response structures to some extent. EBS was described as useful in detecting a large scope of events, reaching remote areas and guiding outbreak response.ConclusionHealth facility and community-based EBS provide valuable information that can strengthen the early warning function of national surveillance systems. Integration into existing early warning and response systems was described as key to generate data for action and to facilitate rapid verification and response. Priority in its implementation should be given to settings that would particularly benefit from EBS strengths. This includes areas most prone to outbreaks and where traditional ‘routine’ surveillance is suboptimal.
Diffusion of knowledge and behaviours among trainee doctors in an acute medical unit and implications for quality improvement work: a mixed methods social network analysis
Authors: Sullivan Paul , Saatchi Ghazal , Younis Izaba , Harris Mary Louise 
Published: December 2019

ObjectivesTo describe the social networks that diffuse knowledge, attitudes and behaviours relating to different domains of practice within teams of trainee doctors in an acute hospital medical setting. The domains examined were ‘clinical-technical’, ‘patient centredness’ and ‘organisation of work’.DesignSequential mixed methods: (i) sociocentric survey of trainee consisting of questions about which colleagues are emulated or looked to for advice, with construction of social network maps, followed by (ii) semi-structured interviews regarding peer-to-peer influence, analysed using a grounded theory approach. The study took place over 24 months.SettingAn acute medical admissions unit, which receives admissions from the emergency department and primary care, in a National Health Service England teaching hospital.ParticipantsTrainee medical doctors working in five consecutive rotational teams. Surveys were done by 39 trainee doctors; then 15 different participants from a maximal diversity sample were interviewed.ResultsClinical-technical behaviours spread in a dense network with rich horizontal peer-to-peer connections. Patient-centred behaviours spread in a sparse network. Approaches to non-patient facing work are seldom copied from colleagues. Highly influential individuals for clinical technical memes were identified; high influencers were not identified for the other domains.ConclusionInformation and influence relating to different aspects of practice have different patterns of spread within teams of trainee doctors; highly influential individuals were important only for spread of clinical-technical practice. Influencers have particular characteristics, and this knowledge could guide leaders and teachers.
Conceptualising post-stroke fatigue: a cross-sectional survey of UK-based physiotherapists and occupational therapists
Authors: Thomas Karen , Hjalmarsson Clarissa , Mullis Ricky , Mant Jonathan 
Published: December 2019

With survival after stroke improving, more people are discharged into the community with multiple and persistent deficits. Fatigue is a common unmet need for stroke survivors, but there are no evidence-based guidelines for its assessment and management. This study explored how UK-based therapists conceptualise post-stroke fatigue (PSF) in current practice.ObjectiveTo describe current understanding of PSF among physiotherapists (PT) and occupational therapists (OT).DesignA cross-sectional online survey using Qualtrics software (a survey creation and analysis programme) was sent to therapists working with stroke survivors in 2019. Responses to the open ended question, ‘How would you describe PSF if approached by another healthcare professional?’ were analysed thematically by two independent researchers.Participants137 survey respondents (71 PT and 66 OT) from a range of clinical settings (25 acute care, 24 sub-acute rehabilitation care, 3 primary care and 85 community care) with 7 months-36 years of experience working with stroke survivors completed the survey.ResultsRespondents stated that PSF should be regarded as an important medical condition because it is common and can be associated with severe symptoms. Symptoms were perceived to be highly variable and the syndrome was difficult to define objectively. It was felt to have both physical and cognitive components. A variety of different opinions were expressed with regard to causation, conceptualisation and best management.ConclusionTherapists working with stroke survivors conceptualise and manage PSF in different ways. Clinical practice is hampered by a lack of a widely adopted definition, and a small evidence base. Research into causes and management of PSF is a priority.
Paediatric palliative care: a systematic review
Authors: Nilsson Stefan , Ohlen Joakim , Hessman Eva , Brännström Margareta 
Published: December 2019

ObjectivesTo review literature relating to evidence, context and facilitation to describe knowledge translation in paediatric palliative care. Paediatric palliative care requires competences including both paediatric specialists as well as services that are developed for this purpose, and there is a need to facilitate paediatric palliative care knowledge translation. Promoting Action on Research Implementation in the Health Services (PARiHS) is a framework for knowledge translation, which highlights the relationships between evidence, context and facilitation. PARiHS framework has been revised and updated in a new version called i-PARiHS.MethodsThe electronic databases AgeLine, CINAHL, The Cochrane Library, PsycINFO, PubMed and Scopus were searched. Papers included were limited to English and Swedish publications and restricted to publications dated between 1993 and August 2019. All types of observational and experimental studies using any research design were included.Results and conclusionsThirty-eight articles were included and there was a common vision about how and when palliative care should be offered to children. The i-PARiHS was used as a lens to describe the knowledge translation in paediatric palliative care. Symptom relief was the most commonly described evidence-based strategy, and the hospital environment was the most commonly described context. Different types of education were the most commonly used strategies to facilitate knowledge translation. The results mainly focused on increasing knowledge of palliative care in paediatric care. To sum up, the results report strategies to achieve knowledge translation of paediatric palliative care, and these can be interpreted as a guideline for how this process can be facilitated.Trial registration numberCRD42018100663.
Comparison of medium to long-term outcomes of acute severe ulcerative colitis patients receiving accelerated and standard infliximab induction
Authors: Gibson David J , Doherty Jayne , McNally Mairead , Campion John , Keegan Denise , Keogh Aine , Kennedy Una , Byrne Kathryn , Egan Laurence J , McKiernan Susan , MacCarthy FInbar , Sengupta Subhasish , Sheridan Juliette , Mulcahy Hugh E , Cullen Garret , Slattery Eoin , Kevans David , Doherty Glen A 
Published: December 2019

IntroductionAccelerated dose infliximab (IFX) induction is associated with reduced short-term colectomy rate in acute severe ulcerative colitis (ASUC). Data on medium/long-term outcomes of this strategy are limited.AimsEvaluate medium/long-term outcomes in patients receiving IFX induction for ASUC, comparing accelerated dose (AD) and standard dose (SD) induction.MethodsRetrospective study of consecutive patients admitted with corticosteroid-refractory ASUC in four tertiary referral centres within INITIative IBD research network (www.initiativeibd.ie). IFX rescue was given either as SD (weeks 0, 2, 6) or AD (<28 days) from January 2010 to September 2017. AD induction has been utilised in participating centres since 2014. Consequently SD patients were subdivided based on time period of IFX rescue: historical SD group (SD1) (2010–2013) and current SD group (SD2) (2014–2017). Primary endpoint was time to colectomy; secondary endpoint was time to IFX discontinuation if induction was complete.Results145 patients received rescue IFX (AD=58, SD1=32, SD2=55). Disease severity at induction was comparable between AD and SD1 groups; however, SD2 group had less severe disease: median C-reactive protein (CRP) 39, 44 and 20 mg/L for AD, SD1 and SD2 groups, respectively (p=0.026, Kruskal-Wallis); median CRP: albumin ratio was 1.4, 1.8 and 0.6 (p=0.016). Median follow-up for AD, SD1 and SD2 groups was 1.6 (IQR 1.1–3.1), 4.9 (IQR 2.6–5.5) and 1.5 (IQR 0.9–2.3) years. Time to colectomy was shorter in SD1 (log rank p=0.0013); no significant difference in time to colectomy was observed comparing AD and SD2 groups (log rank p=0.32). 123 patients (84%) completed IFX induction and received maintenance therapy. Time to IFX discontinuation was shorter in SD1 (log rank p=0.009).ConclusionTime to colectomy is significantly prolonged with use of AD IFX in selected ASUC patients with more severe disease. Historical use of standard IFX induction for all ASUC patients is associated with inferior long-term outcomes.
Causal structures and dynamics of black-hole-like solutions in string theory
Authors: Kang Subeom , Yeom Dong-han 
Published: December 2019

AbstractWe investigate spherically symmetric solutions in string theory. Such solutions depend on three parameters, one of which corresponds to the asymptotic mass while the other two are the dilaton and two-form field amplitudes, respectively. If the two-form field amplitude is non-vanishing, then this solution represents a trajectory of a singular and null hypersurface. If the dilaton and two-form field amplitudes are non-vanishing but very close to zero, then the solution is asymptotically the same as the Schwarzschild solution, while only the near horizon geometry will be radically changed. If the dilaton field diverges toward the weak coupling regime, this demonstrates a firewall-like solution. If the dilaton field diverges toward the strong coupling limit, then as we consider quantum effects, this spacetime will emit too strong Hawking radiation to preserve semi-classical spacetime. However, if one considers a junction between the solution and the flat spacetime interior, this can allow a stable star-like solution with reasonable semi-classical properties. We discuss possible implications of these causal structures and connections with the information loss problem.
New constraints on Lorentz Invariance violation from Crab Nebula spectrum beyond 100 TeV
Authors: Satunin Petr 
Published: December 2019

AbstractRecently two collaborations, Tibet and HAWC, presented new measurements of gamma-ray spectrum from Crab Nebula (Amenomori et al. in Phys Rev Lett 123(5):051101, 2019, arXiv:1906.05521 [astro-ph.HE]; Abeysekara et al. [HAWC Collaboration] in Astrophys. J. 881, 134, (2019), arXiv:1905.12518 [astro-ph.HE]) which continues beyond 100 TeV. We use these data to establish two-sided constraints on parameters of Lorentz Invariance violation in quantum electrodynamics. The limits on Lorentz violating mass scale for quartic dispersion relation are $$4.1\times 10^{14}\, \text{ GeV }$$4.1×1014GeV (photon splitting) and $$1.9\times 10^{13}\, \text{ GeV }$$1.9×1013GeV (photon decay) for superluminal case, and $$1.4\times 10^{12}$$1.4×1012 GeV (suppression of shower formation) for subluminal case.