bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a New Low-Cost Tandem VGT Concept for Turbocharger Applications
Authors: Erdmenger Rodrigo R. , Menter Katya , Giepman Rogier , Clancy Cathal , Vadvadgi Aneesh , Lavertu Tom , Leonard Thomas , Spence Stephen 
Published: August 2018

The air handling system for large diesel/gas engines such as those used on locomotive, marine, and power generation applications require turbochargers with a high reliability and with turbomachinery capable to adjust to different operating conditions and transient requirements. The usage of variable geometry turbocharging (VGT) provides flexibility to the air handling system but adds complexity, cost and reduces the reliability of the turbocharger in exchange for improved engine performance and transient response. For this reason, it was desirable to explore designs that could provide the variability required by the air handling system, without the efficiency penalty of a conventional waste gate and with as little added complexity as possible.
The current work describes a new low-cost variable geometry turbine design to address these requirements. The new tandem nozzle concept proposed is applicable to both axial and radial turbines, and has been designed using conventional 1D models and 2D/3D CFD methods. The concept has furthermore been validated experimentally on two different test rigs. In order to avoid the long lead times of procuring castings, the nozzle for the axial turbine was manufactured using new additive manufacturing techniques. Both the axial turbine and the radial turbine designs showed that the concept is capable to achieve a mass flow variability of more than 15% and provide a robust and cost-effective alternative to conventional VGT designs by significantly reducing the number of moveable parts.
Development of a Non-Contacting Mechanical Seal for High Performance Turbocharger Applications
Authors: Nelson Daniel A. 
Published: August 2018

This paper presents the design and development of a non-contacting dry-gas mechanical seal for high performance automotive turbocharger applications. Turbochargers are increasingly being incorporated into high performance automobile engines to improve fuel efficiency, enhance energy recovery, and increase horsepower as compared with similar sized naturally aspirated engines. Minimizing the wear rate of tribological surfaces in the turbomachinery is critical to maximizing the reliability and durability of the turbocharger.
A dry-gas seal for turbochargers and related technologies with 2 to 4 cm shafts has been developed. The seal provides a complete barrier between the bearing oil and compressor flow path and is capable of reverse pressure and high speed. The seal performance was evaluated for speeds between 60,000 to 80,000 RPM, pressure differentials between −0.8 (reverse pressure) to 6 bar, and temperatures between 20 to 200 °C. Structural and thermal response of the seal components to the operating conditions are analyzed using finite element methods and the tribological behavior of the seal rings are analyzed using computational fluid dynamics. The design is experimentally validated in a seal test stand. This novel approach reduces turbocharger blowby and shows no measurable wear when compared with piston ring seals.
Thermal Performance of the Realistic Leading Edge Cooling Passage of a Turbine Blade
Authors: Song Inhwan , Son Changmin , Yang Jangsik , Lee Changyong , Lee Kidon 
Published: August 2018

The present study focuses on evaluating the thermal performance of the realistic leading edge cooling passage of a turbine blade, experimentally. The detailed heat transfer distributions and pressure loss of the cooling passage are measured with and without rib turbulators for direct comparison.
The experimental model is representing the realistic leading edge cooling passage, which has a converging duct with triangular cross sectional shape. Therefore, the aspect ratio and the cross sectional area of the triangular passage vary significantly along the coolant flow direction. A Perspex test model is designed at 1.3 times large scale to meet Reynolds number similarity. The test model is installed with 45-degree rib turbulators at constant space-to-height ratio of P/e = 10. The experiments are carried out at the Reynolds numbers of 20,000, 40,000 and 80,000. The transient heat transfer test technique using thermochromic liquid crystals (TLCs) was applied to measure the detailed surface heat transfer distributions. The local mixed bulk temperatures (Tmb) are defined using the air thermocouples positioned in the centerline along the cooling passage. The static pressures are measured from the pressure taps machined as a part of the test model so that friction factors of the ribbed cooling passage are also evaluated. The friction factors are influenced by the characteristics of 3 dimensional converging duct of the experimental model. The full surface heat transfer coefficients, friction factors, and overall thermal performance of the cooling passage are reported for the comparison with the other cooling configurations.
LPV Based Sliding Mode Control for Limit Protection of Aircraft Engines
Authors: Yang Shubo , Wang Xi 
Published: August 2018

Limit protection, which frequently exists as an auxiliary part in control systems, is not the primary motive of control but is a necessary guarantee of safety. As in the case of aircraft engine control, the main objective is to provide the desired thrust based on the position of the throttle; nevertheless, limit protection is indispensable to keep the engine operating within limits.
There are plenty of candidates that can be applied to design the regulators for limit protection. PID control with gain-scheduling technique has been used for decades in the aerospace industry. This classic approach suggests linearizing the original nonlinear model at different power-level points, developing PID controllers correspondingly, and then scheduling the linear time-invariant (LTI) controllers according to system states. Sliding mode control (SMC) is well-known with mature theories and numerous successful applications. With the one-sided convergence property, SMC is especially suitable for limit protection tasks. In the case of aircraft engine control, SMC regulators have been developed to supplant traditional linear regulators, where SMC can strictly keep relevant outputs within their limits and improve the control performance.
In aircraft engine control field, we all know that the plant is a nonlinear system. However, the present design of the sliding controller is carried out with linear models, which severely restricts the valid scope of the controller. Even if the gain scheduling technique is adopted, the stability of the whole systems cannot be theoretically proved.
Research of linear parameter varying (LPV) system throws light on a class of nonlinear control problems. In present works, we propose a controller design method based on the LPV model to solve the engines control problem and achieve considerable effectiveness.
In this paper, we discuss the design of a sliding controller for limit protection task of aircraft engines, the plant of which is described as an LPV system instead of LTI models. We define the sliding surface as tracking errors and, with the aid of vertex property, present the stability analysis of the closed-loop system on the sliding surface. An SMC law is designed to guarantee that the closed-loop system is globally attracted to the sliding surface. Hot day (ISA+30° C) takeoff simulations based on a reliable turbofan model are presented, which test the proposed method for temperature protection and verify its stability and effectiveness.
Experimental Analysis of Wave Propagation in a Methane-Fueled Rotating Detonation Combustor
Authors: Welch C. , Depperschmidt D. , Miller R. , Tobias J. , Uddi M. , Agrawal A. K. , Lowe Scott 
Published: August 2018

Recently, pressure gain combustion (PGC) has been a subject of intense study because of its potential to increase the thermodynamic efficiency of power generating gas turbines by several percentage points. The rotating detonation combustion/combustor (RDC) can provide large pressure gain within a small volume through rapid heat release by detonation wave(s) that propagate continuously in the circumferential direction. The RDC has been investigated mainly for propulsion applications using hydrogen fuel. In contrast, we present experimental results from an RDC operated on methane and oxygen-enriched air mixtures to represent the reactants in advanced power generating gas turbines. The propagation of detonation and oblique shock waves in the RDC is investigated through High Speed Video (HSV) imaging and Ion Probe (IP) data.
HSV imaging requires optical access to the RDC, which can be difficult especially when the RDC is integrated with the gas turbine inlet hardware. Additionally, HSV systems are quite expensive. In contrast, IPs are inexpensive and have the advantages of small size and flexibility in the placement location and can be flush mounted causing minimal interference with the propagating wave. In this study, the detonation wave is tracked by high-resolution HSV imaging at framing rate of 200 kHz. At the same time, IPs are used to detect the rotating oblique shock wave inside the RDC, and different analysis techniques are explored to quantify the wave speed. IP voltage data are analyzed by differentiation, correlation and fast-Fourier transform methods to compute the wave speed (or rotation frequency), and the results are compared with those from the HSV image analysis. The uncertainty of different methods is discussed, and finally, the analysis techniques are applied to investigate the wave characteristics during an experiment.
Framework for estimating sleep timing from digital footprints
Authors: Chen Bo-chiuan , Seo Dong-Chul , Lin Hsien-Chang , Crandall David 
Published: August 2018

ObjectiveWe propose a method that estimates sleep timing from publicly observable activity on online social network sites. The method has the potential to minimise participant-related biases, does not require specialised equipment and can be applied to a large population.Materials and methodsWe propose a framework that estimates midpoints of habitual sleep time from activity records on a social media—Twitter. We identified sets of before-bedtime and after-wake-up tweets that marked the periods of reduced Twitter activity, which we use as a proxy of sleep. We then estimated the timing of sleep by deriving the median among midpoints of paired before-bedtime and after-wake-up tweets. Visualisations and examples of our estimates comparing sleep timing of users from different countries are provided.DiscussionInitial results suggest that the proposed framework could detect differences in sleep timing among user groups of different countries. The proposed framework may be a cost-efficient complement for future research regarding sleep-related health concerns. Researchers and practitioners may benefit from accessing habitual sleep data. While validation is still required prior to actual applications, the proposed framework may be a first step towards a convenient and cost-efficient complement to currently available methods.
Development and evaluation of a hospital discharge information package to empower parents in caring for a child with a fever
Authors: van de Maat Josephine S , van Klink Daphne , den Hartogh-Griffioen Anine , Schmidt-Cnossen Eva , Rippen Hester , Hoek Amber , Neill Sarah , Lakhanpaul Monica , Moll Henriette A , Oostenbrink Rianne 
Published: August 2018

ObjectivesFirst, to explore parents’ views on and experiences of managing their febrile child and to assess their behaviour and needs when in search of information about fever; second, to develop and evaluate a hospital discharge information package about fever in children.DesignMixed methods: (A) qualitative study with semistructured interviews and a focus group discussion (FGD) and (B) quantitative survey.SettingEmergency department, non-acute hospital setting and day nursery in Rotterdam, The Netherlands.ParticipantsParents of children <18 years (interviews, n=22) parents of children under 5 years (FGD (n=14), survey (n=38)).InterventionInformation package about fever in children (leaflet and website including videos).Outcome measures quantitative surveyKnowledge of fever and confidence in caring for a febrile child (Likert scale 0–5).ResultsParents found fever mostly alarming, especially high fever. Help-seeking behaviour was based on either specific symptoms or on an undefined intuition. When parents did not feel recognised in their concern or felt criticised, anxiety increased as well as the threshold to seek healthcare for future illnesses. Information was needed, especially for situations when the general practitioner or social network were less easily available. This information should be reliable, consistent, available in multiple formats and include advice on management of fever at home and precise referral to medical services. Parents reported improved knowledge about fever (p<0.05) and mentioned improved confidence in caring for a child with fever at home after consulting the information package.ConclusionParents of children with a fever visiting the hospital are concerned about specific symptoms or based on an undefined intuition. Rather than telling parents that they should manage their child’s illness at home, healthcare professionals should recognise parental intuition and provide clear information on alarming signs and potential diagnoses to empower parents in the management of their febrile child.
Effects of methylphenidate on cognition and behaviour in children with neurofibromatosis type 1: a study protocol for a randomised placebo-controlled crossover trial
Authors: Pride Natalie A , Barton Belinda , Hutchins Paul , Coghill David R , Korgaonkar Mayuresh S , Hearps Stephen J C , Rouel Melissa , Malarbi Stephanie , North Kathryn N , Payne Jonathan M 
Published: August 2018

IntroductionDopamine dysregulation has been identified as a key modulator of behavioural impairment in neurofibromatosis type 1 (NF1) and a potential therapeutic target. Preclinical research demonstrates reduced dopamine in the brains of genetically engineered NF1 mouse strains is associated with reduced spatial-learning and attentional dysfunction. Methylphenidate, a stimulant medication that increases dopaminergic and noradrenergic neurotransmission, rescued the behavioural and dopamine abnormalities. Although preliminary clinical trials have demonstrated that methylphenidate is effective in treating attention deficit hyperactivity disorder (ADHD) symptoms in children with NF1, its therapeutic effect on cognitive performance is unclear. The primary aim of this clinical trial is to assess the efficacy of methylphenidate for reducing attention deficits, spatial working memory impairments and ADHD symptoms in children with NF1.Methods and analysisA randomised, double-blind, placebo-controlled trial of methylphenidate with a two period crossover design. Thirty-six participants with NF1 aged 7–16 years will be randomised to one of two treatment sequences: 6 weeks of methylphenidate followed by 6 weeks of placebo or; 6 weeks of placebo followed by 6 weeks of methylphenidate. Neurocognitive and behavioural outcomes as well as neuroimaging measures will be completed at baseline and repeated at the end of each treatment condition (week 6, week 12). Primary outcome measures are omission errors on the Conners Continuous Performance Test-II (attention), between-search errors on the Spatial Working Memory task from the Cambridge Neuropsychological Test Automated Battery (spatial working memory) and the Inattentive and Hyperactivity/Impulsivity Symptom Scales on the Conners 3-Parent. Secondary outcomes will examine the effect of methylphenidate on executive functions, attention, visuospatial skills, behaviour, fine-motor skills, language, social skills and quality of life.Ethics and disseminationThis trial has hospital ethics approval and the results will be disseminated through peer-reviewed publications and international conferences.Trial registration numberACTRN12611000765921.
Use of a patient-centred educational exchange (PCEE) to improve patient’s self-management of medicines after a stroke: a randomised controlled trial study protocol
Authors: Coombes Judith Ann , Rowett Debra , Whitty Jennifer A , Cottrell W Neil 
Published: August 2018

IntroductionNational and international guidelines make recommendations for secondary prevention of stroke including the use of medications. A strategy which engages patients in a conversation to personalise evidence-based educational material (patient-centred educational exchange; PCEE) may empower patients to better manage their medications.Methods and analysisThis protocol outlines a non-blinded randomised controlled trial. Consenting patients admitted with a diagnosis of stroke or transient ischaemic attack will be randomised 1:1 to receive either a PCEE composed of two sessions, one at the bedside before discharge and one by telephone at least 10 days after discharge from hospital in addition to usual care (intervention) or usual care alone (control). The primary aim of this study is to determine whether a PCEE improves adherence to antithrombotic, antihypertensive and lipid-lowering medications prescribed for secondary prevention of stroke over the 3 months after discharge, measured using prescription-refill data. Secondary aims include investigation of the impact of the PCEE on adherence over 12 months using prescription-refill data, self-reported medication taking behaviour, self-reported clinical outcomes (blood pressure, cholesterol, adverse medication events and readmission), quality of life, the cost utility of the intervention and changes in beliefs towards medicines and illness.Ethics and disseminationCommunication of the trial results will provide evidence to aid clinicians in conversations with patients about medication taking behaviour related to stroke prevention. The targeted audiences will be health practitioners and consumers interested in medication taking behaviour in chronic diseases and in particular those interested in secondary prevention of stroke.The trial has ethics approval from Metro South Human Research Ethics Committee (HREC/15/QPAH/531) and The University of Queensland Institutional Human Research Ethics (2015001612).Trial registration numberACTRN12615000888561; Pre-results.
Automated O2 titration improves exercise capacity in patients with hypercapnic chronic obstructive pulmonary disease: a randomised controlled cross-over trial
Authors: Vivodtzev Isabelle , L’Her Erwan , Vottero Gabrielle , Yankoff Claire , Tamisier Renaud , Maltais François , Lellouche François , Pépin Jean-Louis 
Published: August 2018

Automatically titrated O2 flows (FreeO2) was compared with constant O2 flow on exercise capacity, O2 saturation and risk of hyperoxia-related hypercapnia in patients with severe COPD with baseline hypercapnia and long-term oxygen therapy (LTOT). Twelve patients were enrolled in a randomised double-blind cross-over study to perform exercise with either FreeO2 or constant flow. Endurance time (primary outcome) and SpO2 were both significantly improved with FreeO2compared with constant flow (p<0.04), although pCO2 was similar in both conditions. Automated titration of O2 significantly and clinically improved endurance walking time in patients with severe COPD receiving LTOT, without worsening of pCO2.Trial registration numberResults , NCT01575327
MgB2 superconductor prepared by Mg diffusion method with the addition of reduced graphene oxide
Authors: Li Lei , Zhang Hong , Zhao Yong , Zhang Yong 
Published: August 2018

The effects of 0–5 wt.% reduced graphene oxide (rGO) addition on the superconducting properties of MgB2 bulks were investigated. We found that the dense and uniform MgB2 bulks were obtained by Mg diffusion method with rGO addition. The superconducting properties of MgB2 improved by the addition of rGO content of less than 2 wt.%. With more than 2 wt.% (including 2 wt.%) of rGO addition, nonsuperconducting phase MgB2C2 appeared and MgO content increased, which resulted in a decline in superconducting properties.
Salve os inglórios! Historicidade e memória em O mestre-sala dos mares
Authors: Kater Thiago 
Published: August 2018

A canção O mestre-salados mares, composta por João Bosco e Aldir Blanc e lançada no álbum Caça a Raposa em 1975, é um dos tantos exemplos em que foi possível conciliar a crítica à ditadura e o sucesso mercadológico na indústria fonográ- fica. A canção se estrutura como um discurso histórico elogioso a respeito da Revolta da Chibata. Este ensaio pretende propor uma análise da letra desta canção, entendendo-a enquanto documento histórico ou discurso historiográfico e, portanto, passível de interpretações que permitirão desdobrar conceitos e vinculações teóricas.
The Future of Meritocracy: A Discussion of Daniel Bell’s The China Model
Authors: Zhang Yongle , Howe Colleen 
Published: August 2018

Abstract
Compared to Wang Shaoguang’s approach to re-interpret the old concept “democracy” to overcome the Schumpeterian model of political legitimation, Daniel Bell’s Political Meritocracy takes a more challenging path, attempting to build a new discourse of legitimacy centering on the concept “meritocracy” and incorporating elements of ancient China’s traditions, the socialist revolutions in the twentieth century, and the system of competitive elections common in the Western world today. This inspiring work is full of incisive arguments, but could be improved by further considering the tension between the Confucian tradition and the revolutionary tradition in the twentieth century.
Multiweek Prediction Skill Assessment of Arctic Sea Ice Variability in the CFSv2
Authors: Liu Yanyun , Wang Wanqiu , Kumar Arun 
Published: August 2018

AbstractSkillful Arctic Sea ice prediction is becoming increasingly important because of its societal, industrial, and economic impacts over the polar regions and potential influence on lower-latitude weather and climate variability. In this work, we evaluate the multiweek forecast skill of Arctic sea ice using the Climate Forecast System, version 2 (CFSv2). To the authors’ knowledge, this is the first effort to diagnose and assess the skill of multiweek Arctic sea ice prediction from a coupled atmosphere–ocean model. Analysis of a suite of retrospective 45-day forecasts spanning 1999–2015 shows that CFSv2 captures general features of sea ice concentration (SIC) variability. Total SIC variability is dominated by interannual variability, which accounts for more than 60% of the total variance. Submonthly variability accounts for 29% of the total variance in December, 20% in March and June, and 12.5% in September. We assess the ability of CFSv2 to predict the pan-Arctic SIC, as well as regional SIC in nine Arctic regions. Results show that the SIC prediction skill is highly region dependent (e.g., higher prediction skill for Kara/Barents Seas and lower for the Canadian Archipelago). Overall, the maximum anomaly correlation coefficient (ACC) of SIC for both melt and freeze-up seasons is near the marginal zones, and their spatial distribution shows a relationship with the distribution of the variance. If the ACC of 0.5 is taken as the critical value for skillful prediction, the predictability of weekly SIC near the marginal zones is about 5–6 weeks. Prediction skill for Arctic sea ice extent is above 0.6 for the entire six target weeks and has a large contribution from interannual variability.