bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rotordynamic Characteristics Prediction for Hole-Pattern Seals Using Computational Fluid Dynamics
Authors: Thorat Manish R. , Hardin James R. 
Published: September 2019

Abstract
The experimental setup for a hole-pattern seal is modeled using computational fluid dynamics (CFD) and results compared with measured test data and bulk flow model (ISOTSEAL) predictions. The inlet swirl boundary condition for prior CFD analyses of this test case have either been assumed or based on pitot-tube measurements. In this paper, the validity of each is investigated by including radial inlet nozzles with the inlet plenum in the model geometry. A transient mesh deformation technique with multiple frequency journal excitations is used to determine frequency-dependent rotordynamic coefficients. This multifrequency excitation method is validated against single frequency sinusoidal journal excitation. An empirical limit on the number of frequencies that can be packed in a multifrequency excitation signal to provide a reasonable estimate of rotordynamic coefficients is provided. Rotordynamic coefficients estimated using CFD compare well with measured rotordynamic coefficients. For the given test data, the ISOTSEAL bulk flow model does not provide good correlation for cross-coupled stiffness if the measured swirl ratio at the inlet of the seal is used in the prediction. However, improvement in correlation for cross-coupled stiffness is obtained if the swirl ratio found from CFD analysis is used in the bulk flow model, indicating that pitot-tube measurements of swirl may not be accurate.
Experimental Study on Thermal Contact Resistance Improvement for Optical Fiber by Using Low-Melting Temperature Alloy
Authors: Chu Wen-Xiao , Lin Hao-Yu , Wang Chi-Chuan 
Published: September 2019

Abstract
This paper presents an experimental analysis for minimizing the thermal contact resistance (R) between an optical fiber and copper heat sink by using the low-melting temperature alloy (LMTA) as the thermal interface material (TIM) subject to high-flux operation (up to 250 W ⋅ m−1). For the cases without LMTA, the temperature rise (ΔT) can easily surpass 195 °C at a heating load of 25 W ⋅ m−1. By contrast, ΔT is dramatically reduced to be less than 1 °C with LMTA as TIM with a much higher heating power of 150 W ⋅ m−1. The corresponding thermal resistance (R) can be reduced from 6.5–8.2 K ⋅ m ⋅ W−1 to 0.004–0.013 K ⋅ m ⋅ W−1. The improvement is far superior to existing studies. Besides, decreasing the surface roughness and increasing contact pressure also help to reduce R, especially for the cases when the LMTA is not melted. As the LMTA melts, a significant reduction of R by 56% is achieved as compared to the case without melting. The effect of surface roughness and contact pressure on the thermal contact resistance is also examined, and it is found that the influences are small once LMTA melts.
Impact of Overhead Air Supply Layout on the Thermal Performance of a Container Data Center
Authors: Chu Wen-Xiao , Wu Jui-Lin , Tsui Yeng-Yung , Wang Chi-Chuan 
Published: September 2019

Abstract
This study focused on the improved designs of airflow management in container data centers having overhead air supply. The computational fluid dynamics (CFD) model is first validated with experimental results. Then, the impact of grille diameter, deflector angle, and air supply layout on the data center thermal performance is investigated. The results show that the larger grille diameter may reduce the volumetric flowrate through the upstream grille, causing insufficient air supply and strong hot-air recirculation at the first rack A1. By decreasing the grille diameter from 335 mm to 235 mm, the average rack cooling index (RCI) and supply heat index (SHI) can be improved from 25.4% and 0.292 to 65% and 0.258, respectively. However, implementing small diameter grilles is not an economic way for data center performance improvement as far as the energy consumption is concerned due to the high pumping power. Meanwhile, raising the deflector angle below 30 deg in grille S1 can provide moderate improvement on temperature of the A1 rack. A further rise in the deflector to 40 deg may impose severe deterioration with a pronounced hot-spot area. The data center performance can be improved by changing from center-cold-aisle arrangement to center-hot-aisle layout. The layout provides much higher return air temperature and the RCI and SHI can be improved by 32.7% and 34.5%, respectively.
Efficiency Measurement Approach for a Hydrogen Oxyfuel Combustor
Authors: Tanneberger Tom , Schimek Sebastian , Paschereit Christian Oliver , Stathopoulos Panagiotis 
Published: September 2019

Abstract
Higher shares of variable renewable generation have already raised the demand for energy storage and network services in the power sector. As this trend is expected to continue, the combination of these services in a large scale will be imperative toward a carbon-free power sector. A very promising way to perform this task without any additional emissions is through stoichiometric combustion of the electrolysis products (H2 and O2) in steam and the injection of the generated steam in a conventional steam cycle. However, this can be done only if the product steam has only traces of the two reactants in it, in order to avoid damage of downstream components. The amount of residual gas in the product steam is a direct function of the combustion efficiency. This work analyzes the combustion efficiency of a H2/O2 combustor under steam dilution. As the product gas of such a combustor is primarily steam, the intended efficiency measurement is very challenging and cannot be performed with conventional methods. Instead, an in situ measurement of oxygen and hydrogen is applied. The respective diagnostics and challenges are presented along with the combustion efficiency results. Moreover, a combustor design study is carried out and different flame types (jet and swirl-stabilized flames) are compared. The initial results demonstrate that steam-diluted H2/O2 combustion can achieve an efficiency close to 100%.
Anomaly Detection in Gas Turbine Time Series by Means of Bayesian Hierarchical Models
Authors: Losi Enzo , Venturini Mauro , Manservigi Lucrezia , Ceschini Giuseppe Fabio , Bechini Giovanni 
Published: September 2019

AbstractNowadays, gas turbines (GTs) are equipped with an increasing number of sensors, of which the acquired data are used for monitoring and diagnostic purposes. Therefore, anomaly detection in sensor time series is a crucial aspect for raw data cleaning, in order to identify accurate and reliable data. To this purpose, a novel methodology based on Bayesian hierarchical models (BHMs) is proposed in this paper. The final aim is the exploitation of information held by a pool of observations from redundant sensors as knowledge base to generate statistically consistent measurements according to input data. In this manner, it is possible to simulate a “virtual” healthy sensor, also known as digital twin, to be used for sensor fault identification. The capability of the novel methodology based on BHM is assessed by using field data with two types of implanted faults, i.e., spikes and bias faults. The analyses consider different numbers of faulty sensors within the pool and different fault magnitudes. In this manner, different levels of fault severity are investigated. The results demonstrate that the new approach is successful in most fault scenarios for both spike and bias faults and provide guidelines to tune the detection criterion based on the morphology of the available data.
A Review on the Relationships Between Acoustic Emission, Friction and Wear in Mechanical Systems
Authors: Feng Peipei , Borghesani Pietro , Smith Wade A. , Randall Robert B. , Peng Zhongxiao 
Published: September 2019

Abstract
Acoustic emission (AE) techniques play a key role in machine condition monitoring and wear/fault diagnosis. Understanding the impact of friction and wear on the generation of AE signals is essential to building a reliable wear monitoring system. However, existing papers focus on only one or two factors in specific contact conditions. This paper aims at surveying studies related to both theoretical models and experimental investigations to produce a comprehensive picture of the relationship between tribological parameters (e.g., surface roughness, oil film thickness, and friction coefficient), operating parameters (e.g., sliding velocity and load), and AE signal characteristics (e.g., amplitude/energy, frequency, and event count). This result will provide guidance for the development of AE-based condition monitoring approaches and in particular for the establishment of AE-based wear assessment techniques.
<p><strong>Resistant rose cultivar affects life table parameters of two-spotted spider mite and its predators </strong><strong><em>Phytoseiulus persimilis</em></strong><strong> and </strong><strong><em>Amblyseius swirskii</em></strong><strong> (Phytoseiidae) </strong><strong></strong></p>
Authors: Alipour Zahra , Fathipour Yaghoub , Farazmand Azadeh , Khanamani Mostafa 
Published: September 2019

Herbivores' host plant resistance may also affect performance of their predators. The effect of susceptible ('Yellow') and resistant ('Roulette') rose cultivars on demographic parameters of the two-spotted spider mite (TSSM), Tetranychus urticae Koch and its predators Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) was determined under laboratory conditions. The obtained data were analyzed using the two-sex life table theory. The development rate of different life stages of TSSM and its predators on the susceptible and resistant rose cultivars were signiﬁcantly different. Total development time of juvenile stages of TSSM and A. swirskii on the resistant cultivar was longer than that on the susceptible one, although no significant differences were obtained in the case of P. persimilis. By using the two-sex life table, the intrinsic rate of increase (r) of TSSM on the susceptible and resistant cultivars was 0.205 and 0.143 day-1, respectively. In addition, the net reproductive rate (R0) of TSSM on the susceptible and resistant cultivars was 26.46 and 11.47 eggs per individual, respectively; however, the mean generation time (T) of TSSM on these cultivars was 15.92 and 16.92 days, respectively. Furthermore, the value of the intrinsic rate of increase (r) in P. persimilis on the susceptible and resistant cultivars was 0.217 versus 0.163 day-1as well as in A. swirskii on the mentioned cultivars was 0.147 versus 0.117 day-1, respectively. There was no significant difference between the values of the net reproductive rate (R0) in P. persimilis on the susceptible and resistant rose cultivars, but in A. swirskii the value of this parameter on the susceptible cultivar was significantly higher than that on the resistant one. The mean generation time (T) in both predators on the resistant cultivar was longer than the susceptible one. In conclusion, resistance of the rose cultivar negatively affected the population growth parameters of TSSM and its both predators.
Gastrointestinal lymphoma: the new mimic
Authors: Shirwaikar Thomas Anusha , Schwartz Mary , Quigley Eamonn 
Published: September 2019

BackgroundGastrointestinal (GI) lymphomas comprise a group of distinct clinicopathological entities of B- or T- cell type, with primary gastrointestinal Hodgkin lymphoma being extremely uncommon. The GI tract is the predominant site of extranodal non-Hodgkin lymphoma accounting for 30–40% of all extranodal lymphomas. In the Western world, the stomach is the most commonly involved site followed by the small bowel. Several chronic inflammatory and immune-mediated disorders which predispose to accelerated cell turnover may lead to the malignant transformation of gut lymphocytes and ultimately manifest as GI lymphoma. The challenge for the clinical gastroenterologist is that these tumors may have varied presentations, ranging from nonspecific symptoms such as dyspepsia or bloating to abdominal pain, nausea, vomiting, GI bleeding, diarrhea, weight loss or bowel obstruction.ObjectiveWe illustrate the range of presentations of GI lymphoma with examples based on consecutive cases evaluated at our institution over a 6-month period. These cases demonstrate how appropriately directed endoscopic evaluation with biopsies has the potential to provide a definitive diagnosis and allow the patient to proceed to definitive therapy.ConclusionsThe GI tract is the most commonly involved site for extranodal lymphoma with the stomach being most frequently involved organ.ChronicHelicobacter pyloriinfection, celiac disease, inflammatory bowel disease and autoimmune disorders may predispose to GI lymphoma. This heterogenous group of diseases has varied presentations that may mimic several other GI clinico-pathologic entities. GI lymphomas may be diagnosed with appropriately directed endoscopic evaluation coupled with generous tissue sampling and expert pathologic assessment. Management may range from antibiotic therapy, in the case ofHelicobacter pylori-associated gastric MALT lymphoma, to chemotherapy with or without radiation and, in rare instances, surgery. There are presently no guidelines to direct endoscopic surveillance of GI lymphomas following treatment.
Evaluating the impact of cycle helmet use on severe traumatic brain injury and death in a national cohort of over 11000 pedal cyclists: a retrospective study from the NHS England Trauma Audit and Research Network dataset
Authors: Dodds Nick , Johnson Rowena , Walton Benjamin , Bouamra Omar , Yates David , Lecky Fiona Elizabeth , Thompson Julian 
Published: September 2019

ObjectivesIn the last 10 years there has been a significant increase in cycle traffic in the UK, with an associated increase in the overall number of cycling injuries. Despite this, and the significant media, political and public health debate into this issue, there remains an absence of studies from the UK assessing the impact of helmet use on rates of serious injury presenting to the National Health Service (NHS) in cyclists.SettingThe NHS England Trauma Audit and Research Network (TARN) Database was interrogated to identify all adult (≥16 years) patients presenting to hospital with cycling-related major injuries, during a period from 14 March 2012 to 30 September 2017 (the last date for which a validated dataset was available).Participants11 192 patients met inclusion criteria. Data on the use of cycling helmets were available in 6621 patients.Outcome measuresTARN injury descriptors were used to compare patterns of injury, care and mortality in helmeted versus non-helmeted cohorts.ResultsData on cycle helmet use were available for 6621 of the 11 192 cycle-related injuries entered onto the TARN Database in the 66 months of this study (93 excluded as not pedal cyclists). There was a significantly higher crude 30-day mortality in un-helmeted cyclists 5.6% (4.8%–6.6%) versus helmeted cyclists 1.8% (1.4%–2.2%) (p<0.001). Cycle helmet use was also associated with a reduction in severe traumatic brain injury (TBI) 19.1% (780, 18.0%–20.4%) versus 47.6% (1211, 45.6%–49.5%) (p<0.001), intensive care unit requirement 19.6% (797, 18.4%–20.8%) versus 27.1% (691, 25.4%–28.9%) (p<0.001) and neurosurgical intervention 2.5% (103, 2.1%–3.1%) versus 8.5% (217, 7.5%–9.7%) (p<0.001). There was a statistically significant increase in chest, spinal, upper and lower limb injury in the helmeted group in comparison to the un-helmeted group (all p<0.001), though in a subsequent analysis of these anatomical injury patterns, those cyclists wearing helmets were still found to have lower rates of TBI. In reviewing TARN injury codes for specific TBI and facial injuries, there was a highly significant decrease in rates of impact injury between cyclists wearing helmets and those not.ConclusionsThis study suggests that there is a significant correlation between use of cycle helmets and reduction in adjusted mortality and morbidity associated with TBI and facial injury.
The effect of primary care availability on antibiotic consumption in Hungary: a population based panel study using unfilled general practices
Authors: Biro Aniko , Elek Peter 
Published: September 2019

ObjectiveWe analyse the effect of primary care availability on antibiotic consumption and on the quality of antibiotic prescribing behaviour.DesignRetrospective panel design, secondary analysis of settlement-level administrative panel data (n=2320 settlements, T=72 months).Participants and settingWe analyse antibiotic consumption of the population of villages in Hungary, over years 2010 to 2015. We exploit the geographical and time variation in unfilled (mainly single-handed) general practices as a source of exogenous variation in the availability of primary care. We control for socioeconomic characteristics and settlement fixed effects in a panel regression framework.Outcome measuresAntibiotic expenditures and days of therapy (DOT); consumption of narrow-spectrum and broad-spectrum antibiotics; consumption of Access, Watch and Reserve antibiotics according to the AWaRe categorisation; number of visits to the general practitioner (GP).ResultsIf the general practice of a village becomes unfilled, the number of GP visits decreases on average by 9.3% (95% CI 5.6% to 12.9%), antibiotics DOT decrease on average by 3.2% (95% CI 1.0% to 5.4%) and expenditures on antibiotics decrease on average by 2.5% (95% CI 0.3% to 4.7%). The negative effect on antibiotic consumption is stronger in settlements where secondary care is less available, and where antibiotics were previously overprescribed. The quality of prescribing behaviour measured by the relative changes in the narrow-spectrum vs broad-spectrum as well as the Access versus Watch and Reserve antibiotics deteriorates significantly as a consequence of worse primary care availability.ConclusionsLimited availability of primary care reduces the consumption of antibiotics and at the same time impairs the quality of prescriptions through a decrease of the number of doctor-patient encounters.
Community-based exercise for health promotion and secondary cancer prevention in Canada: protocol for a hybrid effectiveness-implementation study
Authors: McNeely Margaret L , Sellar Christopher , Williamson Tanya , Shea-Budgell Melissa , Joy Anil Abraham , Lau Harold Y , Easaw Jacob C , Murtha Albert D , Vallance Jeffrey , Courneya Kerry , Mackey John R , Parliament Matthew , Culos-Reed Nicole 
Published: September 2019

IntroductionCancer care has expanded from a disease-focused, survival-oriented model to an approach that now considers how survivors can live well in the aftermath of intensive therapy, where they may deal with significant changes to their bodies, mental health or emotional well-being. Research evidence supports the benefit of exercise during and following cancer treatments for cancer-related symptoms, physical functioning and fitness, and health-related quality of life. To move this efficacy evidence into practice, we designed and launched a 5-year study to evaluate the relative benefit from implementing a clinic-to-community-based cancer and exercise model of care.Methods and analysisA hybrid effectiveness and implementation trial design is being used to evaluate the effectiveness of delivery of community-based exercise and to collect data on implementation of the programme. The study opened in January 2017, with estimated completion by January 2022. The programme will be delivered in seven cities across the province of Alberta, Canada, with sites including three academic institutions, six YMCA locations, Wellspring Edmonton and Calgary, and six municipal fitness centres. Participants are adult cancer survivors (n=2500) from all tumour groups and stages and at any time point along their cancer treatment trajectory, up to 3 years post treatment completion. Survivors take part in a minimum of 60 min of mild-to-moderate intensity full body exercise twice weekly for a 12-week period. The primary effectiveness outcome is the proportion of participants meeting or exceeding 150 min of moderate intensity exercise per week at 1-year follow-up. The Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework will be utilised to capture individual-level and organizational-level impact of the exercise programme at 12 and 24 weeks and 1-year follow-up. The cohort of survivors participating in the study will allow for long-term (>5-year) evaluation of rates of cancer recurrence and secondary cancers beyond the funding period.Ethics and disseminationThe study was approved by the Health Research Ethics Board of Alberta. The study is funded by Alberta Innovates and the Alberta Cancer Foundation. The study will help to answer critical questions on the effectiveness of cancer-specific community-based exercise programming in both the short-term and the long-term. Collectively, the findings will help to inform the acceptability, adoption, feasibility, reach and sustainability of community-based exercise.Trial registration numberNCT02984163; Pre-results.
Effects of physical exercise during pregnancy on mothers’ and neonates’ health: a protocol for an umbrella review of systematic reviews and meta-analysis of randomised controlled trials
Authors: Sanabria-Martínez Gema , Poyatos-León Raquel , Notario-Pacheco Blanca , Álvarez-Bueno Celia , Cavero-Redondo Iván , Martinez-Vizcaino Vicente 
Published: September 2019

IntroductionA growing interest has emerged on the effects of exercise during gestation. Several systematic reviews and meta-analyses have shown that prenatal exercise could reduce the mothers’ risk for some disorders. Despite this, evidence regarding the risk of caesarean section, birth weight or Apgar score at delivery is still controversial. Furthermore, practitioners are reluctant to recommend exercise to pregnant women suffering from some disorders, such as hypertension, pre-eclampsia or pregnant women with obesity. Moreover, the scarcity of studies addressing the risks and benefits of exercise at higher intensity prevent practitioners from recommending it at higher dosages. Umbrella reviews represent an appropriate design to elucidate the reasons behind the contradictory findings of previous systematic reviews.MethodsThis protocol was developed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols and the Cochrane Collaboration Handbook. Medline, EMBASE, Web of Science, Cochrane database of systematic reviews, Epistemonikos, Prospero register and SPORTDiscuss databases will be searched to identify systematic reviews, meta-analyses and randomised controlled trials that examine the effect of exercise on pregnancy outcomes from inception to August 2019. Searches will be conducted from September to November 2019.Statistical analysisMethodological quality will be evaluated using the AMSTAR 2 tool. The certainty of evidence and strength of recommendations for meta-analyses will be assessed by the Grading of Recommendations Assessment, Development and Evaluation framework. The summary effect sizes will be calculated through the use of random-effects and fixed-effects models. Heterogeneity among studies will be assessed using the I2statistic, and evidence of excess significance bias and evidence of small study effects will also be evaluated.Ethics and disseminationEthical approval will not be needed for this review protocol. The results will be disseminated to academic audiences by peer-reviewed publications. Furthermore, results will be disseminated to clinical audiences through professionals’ associations and social networks, and may influence guidelines developers in order to improve outcomes in mothers and offspring.PROSPERO registration numberCRD42019123410.