bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical and Experimental Estimation of the Turbine Blade Damper Efficiency
Authors: Shorr Boris , Serebriakov Nikolay , Mel'nikova Galina , Shadrin Dmitri , Vasilyev Boris , Stadnikov Alexander 
Published: August 2018

Prevention of high cycle fatigue failures of blades caused by increased level of vibrational stresses is important problem in engine design and development. Different types of dampers are usually installed under the blade platforms in the region between the shanks of adjacent blades are usually used to reduce the vibrational stresses in the turbine blades. The action of these dampers is based on the vibrational energy dissipation by the dry friction forces arising due to the relative displacement of the contacting surfaces of the damper and the blade. Adoption of a reliable choice of damper design mass and stiffness at the design stage of the aircraft engines requires an experimentally validated estimation of its damping efficiency and its influence on the blade frequency characteristics. The dampers need to be tested under conditions that are maximally close to the operational conditions.
This paper presents an analysis of the stress gauging results of a turbine wheel with box-type dampers of various mass. The tests were carried out on a dynamic bench where resonance oscillations of a stage for a given mode were excited by one of the harmonics to a given rotational speed under the corresponding forces pressing the dampers onto the blade platform. An estimation of the damper efficiency in a wider range of pressing forces was also obtained by conducting the laboratory tests using on a specially designed vibration unit that simulates the dampers effect on a set of three blades.
Numerical analysis of the damper mass and stiffness influence on the frequency and damping characteristics of a real turbine wheel was performed. Obtained experimental data and the GAP model of contact interaction of the insert with blades were used in the MSC. Nastran software package. Analysis showed a satisfactory correlation between the calculated and experimental estimates of the decrease in resonant stresses and resonance frequency changes when the dampers are inserted.
The results presented here confirm the possibility of increasing the reliability of the choice of mass and stiffness of turbine blade dampers at the design stage.
Investigation Into the Impact of Span-Wise Flow Distribution on the Performance of a Mixed Flow Turbine
Authors: Lee Samuel P. , Barrans Simon M. , Jupp Martyn L. , Nickson Ambrose K. 
Published: August 2018

Current trends in the automotive industry towards engine downsizing means turbocharging now plays a vital role in engine performance. A turbocharger increases charge air density using a turbine to extract waste energy from the exhaust gas to drive a compressor.
Most turbocharger applications employ a radial inflow turbine. However, to ensure radial stacking of the blade fibers and avoid excessive blade stresses, the inlet blade angle must remain at zero degrees. Alternately, mixed flow turbines can offer non-zero blade angles while maintaining radial stacking of the blade fibers. The additional freedom to manipulate the blade leading edge and varying tip speed allow for varying leading edge incidence in the span-wise direction. Furthermore, the flow development in the volute does not necessarily lead to uniform inlet conditions.
The current paper investigates the performance of a mixed flow rotor passage under a range of span-wise flow distributions including that produced by a turbine volute. Initial unsteady pulsating simulations were conducted and the volute exit flows extracted. These distributions were then applied as boundary conditions to a single passage model. All simulations were carried out at a constant MFP and average leading edge relative flow angle.
It was observed that the different inlet flow distributions resulted in marked difference in passage flow characteristics. A 2.17% variation was observed between cases in the radial passage. A tilted passage was also included providing an increased axial flow component at the inlet. This passage was found to result in greater swallowing capacity when compared to that of the radial passage.
Computational Modeling of a 1MW Scale Combustor for a Direct Fired sCO2 Power Cycle
Authors: Delimont Jacob , Andrews Nathan , Chordia Lalit 
Published: August 2018

Direct fired oxy-fuel combustion provides a promising method for heat addition into a supercritical carbon dioxide (sCO2) power cycle. Using this method of thermal energy input into the cycle allows for potentially higher fuel to bus bar cycle efficiency. In addition, the nature of the sCO2 power cycle lends itself to easy and efficient capture of 99% of the CO2 generated in the combustion process. sCO2 power cycles typically operate at pressures above 200 bar, and due to the high degree of recuperation found in these cycles, have a very high combustor inlet temperature. Past works have explored combustor inlet temperatures high enough to be in the autoignition regime. The inlet temperatures which will be explored in this work will be limited to 700°C, which will allows for very different combustor geometry than that which has been studied in the past. While this combustor inlet temperature is lower than that previously studied, when combined with the extremely high pressure, this poses several unique and difficult design challenges.
In order to explore these unique design conditions a reliable and robust CFD solution method was developed. This reliable CFD solution methodology enables rapid iteration on various geometries. This paper will explore the CFD modeling setup and the assumptions which were made in the absence of well experimental data in this combustor regime. Exploration of methodology to account for possible variations in chemical kinetics due to the lack of validated kinetic models in the current literature will also be discussed.
The results from the CFD runs will be discussed and the combustor design, and next steps to complete a detailed combustor design will also be discussed. This work will enable future work in the development of oxy-fuel combustors for direct fired sCO2 power. This promising technology enables the use of fossil fuels with up to 99% carbon capture, while maintaining an overall cycle efficiency competitive with natural gas combined cycle power plants.
Crack Growth Resistance of Ceramic Matrix Composites and Anisotropic Stiffness Prediction/Measurement
Authors: Godines Cody , DorMohammadi Saber , Ahmad Jalees , Mansour Rabih , Morscher Gregory N. , Choi Sung , Abdi Frank 
Published: August 2018

A Durability and Damage Tolerance (D&DT) analysis of an S200 Nicalon/SiNC and Oxide/Oxide Ceramic Matrix Composite (CMC) was conducted to determine the crack growth resistance (GIc) of Wedge Loaded DCB (WDCB) at Room and Elevated temperatures (RT/ET) and compared with experimental tests observations. Wedge Loading gives proper crack path without mixed mode effects and can be used at high temperature in a furnace. Load displacement, GIc, electrical resistivity and acoustic emission was measured by tests and compared to FE based Multi Scale Progressive Failure Analysis (PFA) of the WDCB specimen. The critical damage events studied included damage initiation, damage propagation, fracture initiation, and fracture propagation as the components were being loaded.
Effect of defects on Modulus (E11, E22, and E33) was conducted by Electrical Resistance (ER) Measurement at Room temperature (RT). Multi-Scale modeling simulation considered de-homogenized nano-assisted micromechanics analytical formulation, a Mori Tanaka based stiffness correction including void shape, size, distribution and orientation effects. Emitted/received signal amplitude by ER Vs. time was used to evaluate reduction of stiffness in all directions resulting in anisotropic stiffness of As-Built specimens. WDCB specimen was tested to failure at RT/ET to produce reliable GIc values with minimum specimen size. Many parameters that contribute to specimen failure included interface coating thickness, mixed mode failure evolution, interlaminar defects, delamination damage, crack bridging, and fiber fracture which were all studied in detail in this work. All simulations correlated well with test.
Laboratory Method to Evaluate Fog Rejection Effectiveness of Hydrophobic Coatings for Steam Turbine Applications
Authors: Bühlmann Stefan , Limacher Daniela , Manyoky Thomas , Melas Mauro 
Published: August 2018

The application of hydrophobic coatings in steam turbines is expected to partially inhibit the formation of water films on blade surfaces, and consequently reduce the associated efficiency loss and mechanical damage.
Since testing coatings in real steam turbines is impractical, a method is presented to assess, under laboratory conditions, the tendency of materials to reject rather than collect water droplets impinging on them.
This behavior was demonstrated to poorly correlate with wetting angle measurements which proved the necessity to use a more complex approach.
A test rig was therefore used which allows evaluating fog-rejection effectiveness, by placing coated specimens on a rotor and exposing them to a flow of saturated steam carrying micron size droplets. Steam condition, impact angle, droplet size and velocity are kept close to what is expected in low pressure steam turbines.
While rotating, the formed water film is centrifuged and captured in tanks within the supports holding the coated specimens. The mass of their content is measured upon experiment completion. Having tanks in 4 different locations along a specimen’s edge gives an additional insight about variations in collection location and film flow direction.
Repeatability and parameter variation tests have shown that the collection is reasonably insensitive to the changes in operation conditions, yet the scatter in the data remained high. Nevertheless, statistical analysis showed that the method is able to clearly detect differences in collection behavior, thus enabling the industrial partner to select coatings that provide enduring steam turbine efficiency increase.
The effect of acute morphine on obstructive sleep apnoea: a randomised double-blind placebo-controlled crossover trial
Authors: Rowsell Luke , Wong Keith K H , Yee Brendon J , Eckert Danny J , Somogyi Andrew A , Duffin James , Grunstein Ronald R , Wang David 
Published: August 2018

ObjectiveAnaesthesiology guidelines suggest that opioids worsen obstructive sleep apnoea (OSA) despite no randomised controlled trial evidence. We therefore conducted a randomised controlled trial to evaluate the effects of a common clinical dose of morphine on OSA, and to identify clinical phenotype and genotype vulnerability to opioid-respiratory depression.MethodsUnder a double-blind, randomised, crossover design, 60 male patients with OSA attended two visits to the hospital sleep laboratory, at least 1 week apart. Either 40 mg controlled-release oral morphine or placebo was administered. Awake ventilatory chemoreflex tests were performed post dose and prior to overnight polysomnography monitoring. Blood was sampled before sleep and the next morning for toxicology and genotype analyses. Sleep time with oxygen saturation (SpO2) <90% (T90) was the primary outcome.ResultsDespite a large inter-individual variability, 40 mg morphine did not worsen T90 and apnoea–hypopnoea index, and only decreased the SpO2 nadir by 1.3%. In patients with severe OSA, a lower baseline CO2ventilatory response threshold correlated with the worsening of T90, apnoea–hypopnoea index and oxygen desaturation index with morphine use. Patients with OSA and the A118G OPRM1 polymorphism of A/A and A/G had a significantly different morphine effect on awake ventilatory chemosensitivity and T90 during sleep.Conclusions40 mg oral controlled-release morphine did not worsen OSA in men, challenging traditional thinking that OSA will be worsened by opioids. Individual opioid response in patients with OSA may relate to baseline CO2 response threshold and OPRM1 genotype. Our study findings may pave the way for a precision medicine approach to avoid opioid-related risks.Trial registration numberThe Australian and New Zealand Clinical Trial Registry, ACTRN12613000858796.
Awareness, experience and prevalence of heated tobacco product, IQOS, among young Korean adults
Authors: Kim Jinyoung , Yu Hyunjae , Lee Sungkyu , Paek Yu-Jin 
Published: August 2018

IntroductionPhilip Morris International introduced ‘IQOS’ to the Korean market in June 2017. To monitor the use of IQOS among young Korean adults, we identified their awareness, experience and current use of IQOS.MethodsThree months after the introduction of IQOS in Korea, we conducted an online survey with 228 general young adults, aged 19–24 years.Results87 participants (38.1%) were aware of IQOS, 13 (5.7%) were IQOS ever users and 8 (3.5%) were current IQOS users. All the current IQOS users were triple users of conventional cigarettes and electronic cigarettes (e-cigarettes). There were no IQOS-only users and one IQOS ever user was a non-cigarette smoker. Among the eight current IQOS users who smoked 9.1 conventional cigarettes a day on average, four smoked 10–20 HEETS sticks a day. The current IQOS users decided to use IQOS because they believed it was less harmful or to stop smoking. The current conventional cigarette smokers were much more likely to be aware of IQOS (OR 4.496; 95% CI 2.185 to 9.250) and to be IQOS ever users (OR 11.649; 95% CI 1.024 to 132.564).ConclusionAwareness, experience and use of IQOS among young Korean adults were relatively higher than among their Japanese counterparts. Current IQOS users were more likely to smoke conventional cigarettes and/or e-cigarettes, which contradicts the tobacco industry’s claims that conventional cigarette smokers will switch to heated tobacco products. Until obtaining robust evidence concerning heated tobacco products, the government should regulate the tobacco industry’s marketing tactics and health claims.
Assessing progress in protecting non-smokers from secondhand smoke
Authors: Semple Sean , Mueller Will , Leyland Alastair H , Gray Linsay , Cherrie John W 
Published: August 2018

ObjectiveTo examine trends in population exposure to secondhand smoke (SHS) and consider two exposure metrics as appropriate targets for tobacco control policy-makers.DesignComparison of adult non-smokers’ salivary cotinine data available from 11 Scottish Health Surveys between 1998 and 2016.MethodsThe proportions of non-smoking adults who had measurable levels of cotinine in their saliva were calculated for the 11 time points. The geometric mean (GM) concentrations of cotinine levels were calculated using Tobit regression. Changes in both parameters were assessed for the whole period and also for the years since implementation of smoke-free legislation in Scotland in 2006.ResultsSalivary cotinine expressed as a GM fell from 0.464 ng/mL (95% CI 0.444 to 0.486 ng/mL) in 1998 to 0.013 ng/mL (95% CI 0.009 to 0.020 ng/mL) in 2016: a reduction of 97.2%. The percentage of non-smoking adults who had no measurable cotinine in their saliva increased by nearly sixfold between 1998 (12.5%, 95% CI 11.5% to 13.6%) and 2016 (81.6%, 95% CI 78.6% to 84.6%). Reductions in population exposure to SHS have continued even after smoke-free legislation in 2006.ConclusionsScotland has witnessed a dramatic reduction in SHS exposure in the past two decades, but there are still nearly one in five non-smoking adults who have measurable exposure to SHS on any given day. Tobacco control strategies globally should consider the use of both the proportion of non-smoking adults with undetectable salivary cotinine and the GM as targets to encourage policies that achieve a smoke-free future.
“The Italian Job”: Approaching and Tackling Diffuse Soil Pollution in the EU and the Italian Context
Authors: Bevilacqua Paolo , Fermeglia Matteo , Toneatti Luca , Dore Salvatore 
Published: August 2018

Diffuse soil pollution is an example of damage caused by human activities and can be understood in the urban context as a combination of causes due to the presence of various and multiple sources of contamination, such as: car traffic, industrial activities and heating. Importantly, the steadfast expansion of city districts over time has brought either industrial activities to enclose residential areas or (although in a few cases) neighborhoods to envelop previously highly industrialized areas. In Italy, both phenomena represent a widely acknowledged reality, e.g., the municipalities of Taranto and Trieste.
Yet, despite the widespread awareness of the impact of this form of pollution on natural resources and human health, EU environmental legislation depicts an overall picture of fragmentation and poor coordination. Thus, Italian local administrations are striving to devise appropriate methodologies and planificatory measures to bridge such regulatory gap and ultimately find an adequate and comprehensive solution to the problem.
Variations on the Myth of the Abduction of Ganymede
Authors: Strolonga Polyxeni 
Published: August 2018

Abstract
This article explores the verbal and the mythological intertextuality of the archaic Greek sources that relate the abduction of Ganymede and either omit or overemphasize the compensation of horses provided by Zeus to Ganymede’s father. By employing focalization, I trace the myth’s re-presentation in different narrative contexts and I investigate its reception by Hellanicus and Apollodorus. I argue that although the myth is tailored differently according to the narrative purposes of each work, its narratological function as a hortatory analepsis and a celebratory myth is consistent.
On Mapping the Diapycnal Water Mass Transformation of the Upper North Atlantic Ocean
Authors: Xu Xiaobiao , Rhines Peter B. , Chassignet Eric P. 
Published: August 2018

AbstractDiapycnal water mass transformation is the essence behind the Atlantic meridional overturning circulation (AMOC) and the associated heat/freshwater transports. Existing studies have mostly focused on the transformation that is forced by surface buoyancy fluxes, and the role of interior mixing is much less known. This study maps the three-dimensional structure of the diapycnal transformation, both surface forced and mixing induced, using results of a high-resolution numerical model that have been shown to represent the large-scale structure of the AMOC and the North Atlantic subpolar/subtropical gyres well. The analyses show that 1) annual mean transformation takes place seamlessly from the subtropical to the subpolar North Atlantic following the surface buoyancy loss along the northward-flowing upper AMOC limb; 2) mixing, including wintertime convection and warm-season restratification by mesoscale eddies in the mixed layer and submixed layer diapycnal mixing, drives transformations of (i) Subtropical Mode Water in the southern part of the subtropical gyre and (ii) Labrador Sea Water in the Labrador Sea and on its southward path in the western Newfoundland Basin; and 3) patterns of diapycnal transformations toward lighter and denser water do not align zonally—the net three-dimensional transformation is significantly stronger than the zonally integrated, two-dimensional AMOC streamfunction (50% in the southern subtropical North Atlantic and 60% in the western subpolar North Atlantic).
Walking the Tightrope of Socialist Governance: A Strategic-Relational Analysis of Twenty-first-Century Socialism
Authors: Nelson Marcel 
Published: August 2018

The process of socialist transformation in a democratic context presents many quandaries including walking a tightrope between pursuing substantive transformation that challenges existing social relations and remaining in power in view of political opposition stemming from such a challenge. The experiences of twenty-first-century socialism in Ecuador, Bolivia, and Venezuela provide different examples of ways of balancing the two imperatives. Nicos Poulantzas’s writings on the state shed light on the importance of deepening democracy as part of any process of socialist transformation and on the limits of such a strategy. El proceso de transformación socialista en un contexto democrático presenta muchos dilemas que incluyen caminar en la cuerda floja entre perseguir una transformación sustantiva que desafía las relaciones sociales existentes y permanecer en el poder en vista de la oposición política que surge de tal desafío. Las experiencias del socialismo del siglo XXI en Ecuador, Bolivia y Venezuela proporcionan diferentes ejemplos de formas de equilibrar los dos imperativos. Los escritos de Nicos Poulantzas sobre el estado arrojan luz sobre la importancia de profundizar la democracia como parte de cualquier proceso de transformación socialista y los límites de dicha estrategia.
Neoadjuvant chemotherapy in high-risk ovarian cancer patients: Role of age
Authors: Cioffi Raffaella , Bergamini Alice , Rabaiotti Emanuela , Petrone Micaela , Pella Francesca , Ferrari Davide , Mangili Giorgia , Candiani Massimo 
Published: August 2018

Objective: To review a single-center clinical experience with neoadjuvant chemotherapy (NACT) in a population of frail epithelial ovarian cancer (EOC) patients and investigate the prognostic role of advanced age. Methods: We retrospectively reviewed clinical data from 102 advanced EOC patients treated with NACT and presenting high perioperative risk. Patients were divided into 2 groups: group A, including patients aged 70 years or older; and group B, including patients below 70 years old. Univariate and multivariate analyses were performed to compare survival and prognostic factors for survival between the two groups. Results: Forty-two patients (41.2%) were older than 70 years. Elderly patients were more likely to present comorbidities ( p = 0.0001), poor performance status ( p = 0.04), and multiple indications for NACT ( p = 0.03). They showed a reduced response to NACT, since only 64% of elderly patients underwent surgical debulking (98.3% vs 64.3%, p = 0.001) and, among these, half of them were optimally debulked (79.3% vs 50%, p = 0.01). Median progression-free survival (PFS) and overall survival (OS) were significantly lower in group A (respectively, 9 vs 13 months, p = 0.005, and 21 vs 29 months, p = 0.01). Advanced age, IV stage, presence of ascites, and residual disease >1 cm were significantly associated with a lower PFS. However, when analyzing factors associated with OS, the only significant ones were higher American Society of Anesthesiologists score and residual disease >1 cm. Conclusions: Age was not found to be a prognostic factor for survival. This highlights the necessity of validated geriatric assessment tools predicting functional age and treatment tolerability to avoid undertreatment of elderly patients.