bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Hull Flexibility on the Structural Dynamics of a Tension Leg Platform Floating Wind Turbine
Authors: Silva de Souza Carlos Eduardo , Bachynski Erin E. 
Published: September 2019

AbstractDynamic analysis of floating wind turbines often considers the hull as a rigid body. This paper explores the consequences of modeling the pontoons of a tension leg platform (TLP) wind turbine as flexible beams. The analysis is based on numerical simulations of free decays, structural response to wave excitation, and short-term fatigue damage accumulation at tower base and tendons. In addition, the importance of hydroelastic effects due to the pontoons’ vertical deformations is evaluated. Pontoon flexibility changed the platform natural periods and motion amplitude significantly, and the adoption of flexible pontoons reduced the predicted fatigue damage in the tower base and tendons. On the other hand, hydroelasticity had negligible consequences for motion and load responses considered here.
Degree of Freedom and Dynamic Analysis of the Multi-Loop Coupled Passive-Input Overconstrained Deployable Tetrahedral Mechanisms for Truss Antennas
Authors: Xu Yundou , Chen Yang , Liu Wenlan , Ma Xiaofei , Yao Jiantao , Zhao Yongsheng 
Published: September 2019

Abstract
Recently, the truss antennas with deployable tetrahedron unit mechanisms have been successfully applied in orbit, owing to the advantages of large calibers, high accuracy, and large folding ratios. As multiloop coupled mechanisms, deployable tetrahedral mechanisms have multiple different output links, whose supporting limbs connecting output links and the base are mutually coupled. These mechanisms are also called the passive-input overconstrained mechanisms because their passive torsion springs are used as drivers and because the number of the drivers contained is more than the degrees of freedom (DOFs). In this work, a method based on the equivalent concept of first link-removing and then restoring is proposed for the DOF analysis of the multiloop coupled deployable tetrahedral mechanisms. With one coupled chain removed, the equivalent serial chains between the coupled components and the base are established in the remainder of the mechanisms. Then, the coupled chain removed is restored and the equivalent of the multiloop coupled mechanisms is obtained. The Lagrange method is used to establish the dynamic equation of the passive-input overconstrained mechanisms; the influence of the stiffness and number of torsion springs on the unfolding motion is examined.
Design, Construction, and Control of Curves and Surfaces via Deployable Mechanisms
Authors: Ramadoss Vishal , Zlatanov Dimiter , Ding Xilun , Zoppi Matteo , Lyu Shengnan 
Published: September 2019

AbstractThere has been an increasing interest in design and construction of deployable mechanisms (DMs) with multiple degrees of freedom (DOFs). This paper summarizes a family of deployable mechanisms that approximates a series of curves and surfaces using the polygonal approximation technique. These mechanisms are obtained by linking the two- and three-dimensional deployable units, which are constitutive of Sarrus and scissor linkages. Multiple unit mechanisms with varying sizes are assembled and alter their shape within a different family of parameterized curves and surfaces. A systematic methodology for polygonal approximation method is presented. Quadratic, semi-cubic, cubic, quartic and sextic curve boundaries, and quadric surfaces are approximated and controlled. Computer-aided design (CAD) models and kinematic simulations elucidate the mechanism’s ability to approximate a set of curves and surfaces.
Investigation of Tool Errors and Their Influences on Tooth Surface Topography for Face-Hobbed Hypoid Gears
Authors: Liang Chengcheng , Song Chaosheng , Zhu Caichao , Wang Yawen , Liu Siyuan , Sun Ruihua 
Published: September 2019

Abstract
Tool errors are inevitable in an actual gear-manufacturing environment and may directly affect the accuracy of machined tooth surfaces. In this paper, tool errors including spheric radius, pressure angle, rake angle, regrind angle, and cutting side relief angle errors for three-face blade are defined and considered to establish the accurate tooth surface mathematical model for face-hobbed hypoid gears based on the manufacturing process and the meshing theory. The simulation flowchart for tooth surface modeling and tooth surface topography deviation analysis are proposed and performed. Results show that the tooth surface deviation is positive with positive spheric radius and rake angle errors and contrary results can be found for other three tool errors. In addition, the impact of the pressure angle error is the strongest. In addition, the rake angle error has the weakest effect and the influence of spheric radius error on the tooth surface deviation is unsubstantial. For location of tooth surface deviation, the maximum deviation is at the top on the heel and the minimum deviation is at the middle on the toe for spheric radius error. The maximum and minimum deviations are at the top and the middle tooth on the heel for other factors, respectively.
Numerical Simulation of Flow and Thermal Behavior of Radiating Gas Flow in Plane Solar Heaters
Authors: Foruzan Nia Mohammad , Gandjalikhan Nassab Seyyed Abdolreza , Ansari Amir Babak 
Published: September 2019

Abstract
In this paper, the radiating effect of working gas on thermal performance of plane solar heaters is investigated. In the numerical simulation of gas flow, the continuity and momentum equations are solved using the finite volume method (FVM) in which the pressure–velocity coupling is handled by the SIMPLE algorithm. To obtain the temperature distribution, the conservation of energy in the fluid and solid media is solved by the finite difference technique. The distribution of radiating intensity which is needed to calculate the radiative term in the gas energy equation is computed by numerical solution of the radiative transfer equation (RTE) using the discrete ordinate method (DOM). The effect of the variation of different parameters on the predicted thermal efficiency of plane solar heater is investigated by presenting the performance plot. The obtained results show that when the gas medium participates in radiation, the gas temperature at the outlet section increases considerably, especially at high optical thicknesses. Also, the temperature difference between the absorber plate and flowing gas decreases, and more uniform temperature distribution takes place inside the solar heater, which leads to a considerable increase in thermal efficiency. Comparison between the present numerical results and the experimental data published in literature shows good agreement.
Effect of Fuel Injection Pressure and Engine Speed on Performance, Emissions, Combustion, and Particulate Investigations of Gasohols Fuelled Gasoline Direct Injection Engine
Authors: Sharma Nikhil , Agarwal Avinash Kumar 
Published: September 2019

Abstract
Fuel availability, global warming, and energy security are the three main driving forces, which determine suitability and long-term implementation potential of a renewable fuel for internal combustion engines for a variety of applications. Comprehensive engine experiments were conducted in a single-cylinder gasoline direct injection (GDI) engine prototype having a compression ratio of 10.5, for gaining insights into application of mixtures of gasoline and primary alcohols. Performance, emissions, combustion, and particulate characteristics were determined at different engine speeds (1500, 2000, 2500, 3000 rpm), different fuel injection pressures (FIP: 40, 80, 120, 160 bars) and different test fuel blends namely 15% (v/v) butanol, ethanol, and methanol blended with gasoline, respectively (Bu15, E15, and M15) and baseline gasoline at a fixed (optimum) spark timing of 24 deg before top dead center (bTDC). For a majority of operating conditions, gasohols exhibited superior characteristics except minor engine performance penalty. Gasohols therefore emerged as serious candidate as a transitional renewable fuel for utilization in the existing GDI engines, without requirement of any major hardware changes.
Multicriteria Analysis for Retrofitting of Natural Gas Melting and Heating Furnaces for Sustainable Manufacturing and Industry 4.0
Authors: Arnal Álvaro J. , Díaz-Ramírez Maryori , Acevedo Luis , Ferreira Víctor J. , García-Armingol Tatiana , López-Sabirón Ana M. , Ferreira Germán 
Published: September 2019

Abstract
Different retrofitting measures can be implemented at different levels of the industrial furnace, such as refractory layers, energy recovery solutions, new burners and fuel types, and monitoring and control systems. However, there is a high level of uncertainty about the possible implications of integrating new technologies, not only in the furnace but also on the upstream and downstream processes. In this regard, there is a lack of holistic approaches to design the optimal system configurations under a multicriteria perspective, especially when innovative technologies and multi-sectorial processes are involved. The present work proposes a holistic approach to natural gas melting and heating furnaces in energy-intensive industries. A multicriteria analysis, based on criteria and subcriteria, is applied to select the most profitable retrofitting solution using the analytic hierarchy process and stakeholder expertise. The methodology is based on technical indicators, i.e., life cycle assessment, life cycle cost, and thermoeconomic analysis, for evaluating the current state of existing natural gas furnaces. Once the current state is characterized, the methodology determines the potential of efficiency improvement, environmental impact reduction, and cost-savings caused mainly by the implementation of new retrofitting solutions including new refractories, new burner concepts (co-firing), and innovative energy recovery solutions based on phase change materials. Therefore, this methodology can be considered as the first stage that guarantees technical, environmental, and economic feasibility in evaluating the effects of new technologies on the overall system performance.
Time-Space Spectral Method for Rotor–Rotor/Stator–Stator Interactions
Authors: Huang Xiuquan , Wang Ding Xi 
Published: September 2019

AbstractThe paper presents a time-space spectral method for an efficient analysis of rotor–rotor/stator–stator interactions in the framework of the time spectral form harmonic balance method. The method treats time and space harmonics in a coherent way and allows for easy choice of time and passage through the introduction of pseudo-shaft frequency and composite frequency. The proposed method can accommodate passage to passage variation of time-averaged flow field and amplitude of unsteady flow field of a given frequency as needed for rotor–rotor/stator–stator interactions. Minimum change is required to extend an existing harmonic balance flow solver to incorporate the proposed method. The proposed method is the most concise and the simplest one of its kind so far. The first three blade rows of a two-stage fan are used as a test case to demonstrate the validity and effectiveness of the proposed method. Numerical results demonstrate the necessity of including rotor–rotor/stator–stator interaction in an analysis using a frequency-domain method and the capability of the proposed method for such a purpose. It is also concluded from the case study that extra spatial and temporal harmonics are needed to adequately analyze a rotor–rotor/stator–stator interaction.
Multiple sulfur isotopes reveal a possible non-crustal source of sulfur for the Bushveld Province, southern Africa
Authors: Magalhães Nivea , Farquhar James , Bybee Grant , Penniston-Dorland Sarah , Rumble Douglas , Kinnaird Judith , McCreesh Matthew 
Published: September 2019

Abstract
The source of sulfur for sulfide mineralization is a major question for the origin of platinum group element deposits such as the Rustenburg Layered Suite (RLS) of the Bushveld Complex and the nearby Waterberg Project (WP; a large palladium-dominant deposit) in southern Africa. Both deposits are mafic-ultramafic intrusions associated with the ca. 2.06 Ga Bushveld magmatism but are hosted in distinct country rocks. This contrast allows a critical assessment of the contribution upper crustal assimilation provides to sulfide mineralization, and refinement of our understanding of sources of mass-independent fractionated sulfur (MIF-S) to these intrusions. The WP has a signature of anomalous sulfur (average Δ33S = 0.113‰ ± 0.016‰, 1 s.d.), similar to the RLS (avgerage Δ33S = 0.137‰ ± 0.025‰, 1 s.d.). There is no evidence for influence of host rock as a source of anomalous sulfur. The lack of a significant variation of Δ33S values within the WP stratigraphy, and the distinct upper continental crust into which the WP magmas would have been emplaced, shows that addition of upper crustal sulfur is not necessary for PGE formation. This suggests that contamination of WP and RLS magmas with a surface-derived component of Archean age occurred at depth, prior to emplacement.
Paleogene global cooling–induced temperature feedback on chemical weathering, as recorded in the northern Tibetan Plateau
Authors: Fang Xiaomin , Galy Albert , Yang Yibo , Zhang Weilin , Ye Chengcheng , Song Chunhui 
Published: September 2019

Abstract
Plate-tectonic processes have long been thought to be the major cause of the Cenozoic global carbon cycle, and global cooling by uplift of the Tibetan Plateau through enhancing silicate weathering and organic carbon burial and/or by weathering of obducted ophiolites during the closure of the Neo-Tethys Ocean. However, the imbalance resulting from accelerated CO2 consumption and a relatively stable CO2 input from volcanic degassing during the Cenozoic should have depleted atmospheric CO2 within a few million years; therefore, a negative feedback mechanism must have stabilized the carbon cycle. Here, we present the first almost-complete Paleogene silicate weathering intensity (SWI) records from continental rocks in the northern Tibetan Plateau showing that silicate weathering in this tectonically inactive area was modulated by global temperature. These findings suggest that Paleogene global cooling was also strongly influenced by a temperature feedback mechanism, which regulated silicate weathering rates and hydrological cycles and maintained a nearly stable carbon cycle. It acted as a negative feedback by decreasing CO2 consumption resulting from the lower SWI and the kinetic limitations in tectonically inactive areas.
The effects of differential compaction on clinothem geometries and shelf-edge trajectories
Authors: Beelen Daan , Jackson Christopher A.-L. , Patruno Stefano , Hodgson David M. , Trabucho Alexandre João P. 
Published: September 2019

AbstractThe geometry of basin-margin strata documents changes in water depth, slope steepness, and sedimentary facies distributions. Their stacking patterns are widely used to define shelf-edge trajectories, which reflect long-term variations in sediment supply and relative sea-level change. Here, we present a new method to reconstruct the geometries and trajectories of clinoform-bearing basin-margin successions. Our sequential decompaction technique explicitly accounts for downdip lithology variations, which are inherent to basin-margin stratigraphy. Our case studies show that preferential compaction of distal, fine-grained foresets and bottomsets results in a vertical extension of basin-margin strata and a basinward rotation of the original shelf-edge trajectory. We discuss the implications these effects have for sea-level reconstructions and for predicting the timing of sediment transfer to the basin floor.
Accuracy of magnetic resonance imaging texture analysis in differentiating low-grade from high-grade gliomas: systematic review and meta-analysis
Authors: Wang Qiangping , Lei Deqiang , Yuan Ye , Zhao Hongyang 
Published: September 2019

ObjectivesTexture analysis (TA) is a method used for quantifying the spatial distributions of intensities in images using scanning software. MRI TA could be applied to grade gliomas. This meta-analysis was performed for assessing the accuracy of MRI TA in differentiating low-grade gliomas from high-grade ones.MethodsPubMed, Cochrane Library, Science Direct and Embase were searched for identifying suitable studies from their inception to 1 September 2018. The quality of the studies was evaluated on the basis of the Quality Assessment of Diagnostic Accuracy Studies guidelines. We estimated the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnostic OR (DOR) using the summary receiver operating characteristic (SROC) for identifying the accuracy of MRI TA in grading gliomas. Fagan nomogram was applied for assessing the clinical utility of TA.ResultsSix studies including 440 patients were included and analysed. The pooled sensitivity, specificity, PLR, NLR and DOR with 95% CIs were 0.93 (95% CI 0.88 to 0.96), 0.86 (95% CI 0.81 to 0.89), 6.4 (95% CI 4.8 to 8.6), 0.08 (95% CI 0.05 to 0.15) and 78 (95% CI 39 to 156), respectively. The SROC curve showed an area under the curve of 0.96 (95% CI 0.93 to 0.97). Deeks test confirmed no significant publication bias in all studies. Fagan nomogram revealed that the post-test probability increased by 43% in patients with positive pre-test.ConclusionsThe findings of this meta-analysis suggested that MRI TA has high accuracy in differentiating low-grade gliomas from high-grade ones. A standardised methodology is warranted to guide the use of this technique for clinical decision-making.
N-terminal pro-B-type natriuretic peptide and outcomes in type B aortic dissection in China: a retrospective multicentre study
Authors: Luo Changjun , Zhou Jianwei , Xiong Si , Kang Zhongqiang , Zhang Jing , Sun Yifan , Qin Biyun , Fang Kuaifa 
Published: September 2019

ObjectivesN-terminal pro-B-type natriuretic peptide (NT-pro-BNP) is an unfavourable factor responsible for poor outcomes in the cardiovascular diseases. Nevertheless, the prognostic role of NT-pro-BNP in type B aortic dissection (TBAD) remains unclear. The aim of the current study was to investigate the relationship between NT-pro-BNP levels and in-hospital and long-term adverse prognosis in patients with TBAD.DesignA retrospective multicentre study.SettingLiutie Central Hospital, Nanfang Hospital and Huiyang Hospital in China.ParticipantsA total of 657 consecutive patients with TBAD were enrolled in the study. NT-pro-BNP was measured at admission and included patients were divided into three groups according to the tertiles of NT-pro-BNP (pg/mL): <95 (n=220), 95–312 (n=218) and >312 (n=219).Primary and secondary outcome measuresLong-term mortality and in-hospital major adverse clinical events.ResultsOverall, in-hospital death occurred in 27 patients (4.1%), which was significantly higher in upper tertiles of NT-pro-BNP (0.5% vs 4.1% vs 7.8%, p<0.001). The incident of in-hospital major adverse clinical events increased along with higher NT-pro-BNP (1.4% vs 11.5% vs 15.5%, p<0.001). NT-pro-BNP >210 pg/mL had 81.5% sensitivity and 58.6% specificity for predicting in-hospital death (area under the curve= 0.774, 95% CI 0.692 to 0.855; p<0.001). After a median of 3.1 years of follow-up, 97 (14.8%) patients died. The Kaplan-Meier analysis indicated that the long-term cumulative mortality was higher in patients with NT-pro-BNP >210 pg/mL compared with patients with NT-pro-BNP ≤210 pg/mL (log-rank=26.92, p<0.001). In multivariable Cox survival modelling, NT-pro-BNP >210 pg/mL was independently associated with long-term death (adjusted HR 2.47, 95% CI 1.45 to 4.22, p=0.001).ConclusionsNT-pro-BNP resulted as an independent predictor of adverse prognosis in patients with TBAD, thus could be used as a potential risk-stratification tool.
Selective reporting bias in randomised controlled trials from two network meta-analyses: comparison of clinical trial registrations and their respective publications
Authors: Wong Eric KC , Lachance Chantelle C , Page Matthew J , Watt Jennifer , Veroniki Areti , Straus Sharon E , Tricco Andrea C 
Published: September 2019

ObjectiveTo determine (i) the difference in the frequency of serious adverse events (SAEs) reported in trial registrations and their respective primary publications and (ii) the effect of adding SAE data from registries to a network meta-analysis (NMA) in changing the surface under the cumulative ranking (SUCRA) curve values of interventions.DesignSecondary analysis of primary publications from two NMAs.Eligibility criteria for selecting studiesWe included randomised trials published in English after 2005 that were included in two NMAs of pharmacological interventions for Alzheimer’s disease and chronic obstructive pulmonary disease.Data extractionTwo reviewers independently searched multiple international trial registries for registration status and abstracted data from the included study publications and ClinicalTrials.gov.ResultsOf the 203 randomised trials included, 140 (69.0%) were registered with a trial registry and 72 (35.5%) posted results in the registry. The proportion of registered trials increased over time (38.5% in 2005 vs 78.6% in 2014). Of the publications with results posted in a trial registry, 14 (19.4%) had inconsistent reporting of overall SAEs; 7 (10.4%) studies did not report SAEs in the publication but did in the registry. In the 134 randomised trials with a prespecified primary outcome in the registry, 19 studies (9.4%) had a change in the primary outcome in the publication. Adding SAEs reported in registries to the NMAs did not affect the ranking of interventions.ConclusionWe identified inconsistent reporting of SAEs in randomised trials that were included in two NMAs. Findings highlight the importance of including trial registries in the grey literature search and verifying safety data before incorporating it into NMAs.Study registrationosf.io/mk6dr.
How do early-life factors explain social inequalities in adolescent mental health? Findings from the UK Millennium Cohort Study
Authors: Straatmann Viviane S , Lai Eric , Lange Theis , Campbell Melisa Claire , Wickham Sophie , Andersen Anne-Marie Nybo , Strandberg-Larsen Katrine , Taylor-Robinson David 
Published: September 2019

BackgroundReducing inequalities in adolescent mental health is a public health priority, yet the pathways that link social conditions to mental health outcomes in the early years are unclear. We aimed to evaluate the extent to which early years risk factors explain social inequalities in adolescent mental health in the UK.MethodsWe analysed data from 6509 children captured in the UK Millennium Cohort Study. Mental health was assessed through the socioemotional behavioural problems at age 14 (Strengths and Difficulties Questionnaire). The main exposure was maternal education at birth, used as a measure of childhood socioeconomic conditions (SECs), and used to calculate the relative index of inequality. Using causal mediation analysis, we assessed how perinatal, individual child, family, peer relation and neighbourhood-level factors measured up to age 3-mediated the total effect (TE) of SECs on adolescent socioemotional behavioural problems, estimating the proportion mediated and natural indirect effect (NIE) via each block of mediators, and all mediators together.ResultsChildren of mothers with no qualification were almost four times as likely to have socioemotional behavioural problems compared with degree plus level (relative risk (RR) 3.82, 95% CI 2.48 to 5.88). Overall, 63.9% (95% CI 50.2% to 77.6%) (NIE RR 1.97, 95% CI 1.63 to 2.37) of the TE (RR 4.40, 95% CI 3.18 to 6.07) of social inequalities on risk of adolescent socioemotional behavioural problems was mediated by early-life factors.ConclusionsAbout two-thirds of the social inequality in adolescent mental health was explained by early risk factors measured by age 3, highlighting the importance of public health interventions in this period.