bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Efficient Prediction Method for the Azimuthal Migration of Combustion Inhomogeneity in Multi-Stage Cooled Turbines
Authors: He Qingfu , Chi Zhongran , Zang Shusheng 
Published: September 2021

Abstract
The outlet temperature of combustor is commonly monitored by thermocouples at the turbine exhaust. In order to establish the corresponding relationship between the temperature measured by each thermocouple and the working state of each burner, the azimuthal migration of the combustion hot/cold streaks in the multi-stage turbines needs to be quantified. Experiments to measure this migration have high cost and considerable error. It is also difficult to quantify the migration under multiple working conditions. Three-dimensional full-annulus unsteady simulation can obtain this migration. But the unsteady simulation of a single working condition could take several weeks, which is too expensive for engineering usage.
A method named Steady-state Computation of Azimuthal Migration (SCAM) is proposed in this paper. By establishing and solving the transport equation of the migration angle, the azimuthal migration of hot/cold streaks can be predicted by steady-state numerical simulation using the mixing plane at rotor-stator interface. The migration computed by this method is compared with the full-annulus unsteady simulation results in multiple working conditions. The results of SCAM method show good agreement with full-annulus simulations, while costing only 0.01% of the CPU hours. It is also found that the error of SCAM is mainly caused by the fixed boundary value at coolant source terms. The optimal spanwise location of the thermocouples at turbine exhaust is discussed based on the results. The method proposed could be applied to the fault diagnosis and precise repair of the combustors of gas turbines.
Comparison of Performance of Flamelet Generated Manifold Model With That of Finite Rate Combustion Model for Hydrogen Blended Flames
Authors: Shrivastava Sourabh , Verma Ishan , Yadav Rakesh , Nakod Pravin , Orsino Stefano 
Published: September 2021

Abstract
International Air Transport Association (IATA) sets a 50% reduction in 2005 CO2 emissions levels by 2050, with no increase in net emissions after 2020 [1]. The association also expects the global aviation demand to double to 8.2 billion passengers per year by 2037. These issues have prompted the aviation industry to focus intensely on adopting sustainable aviation fuels (SAF). Further, reduction in CO2 emission is also an active area of research for land-based power generation gas turbine engines. And fuels with high hydrogen content or hydrogen blends are regarded as an essential part of future power plants. Therefore, clean hydrogen and other hydrogen-based fuels are expected to play a critical role in reducing greenhouse gas emissions in the future. However, the massive difference in hydrogen’s physical properties compared to hydrocarbon fuels, ignition, and flashback issues are some of the major concerns, and a detailed understanding of hydrogen combustion characteristics for the conditions at which gas turbines operate is needed. Numerical combustion analyses can play an essential role in exploring the combustion performance of hydrogen as an alternative gas turbine engine fuel. While several combustion models are available in the literature, two of the most preferred models in recent times are the flamelet generated manifold (FGM) model and finite-rate (FR) combustion model. FGM combustion model is computationally economical compared to the detailed/reduced chemistry modeling using a finite-rate combustion model. Therefore, this paper aims to understand the performance of the FGM model compared to detailed chemistry modeling of turbulent flames with different levels of hydrogen blended fuels. In this paper, a detailed comparison of different combustion characteristics like temperature, species, flow, and NOx distribution using FGM and finite rate combustion models is presented for three flame configurations, including the DLR Stuttgart jet flame [2], Bluff body stabilized Sydney HM1 flame [3] and dry-low-NOx hydrogen micro-mix combustion chamber [4]. One of the FGM model’s essential parameters is to select a suitable definition of the reaction progress variable. The reaction progress variable should monotonically increase from the unburnt region to the burnt region. The definition is first studied using a 1D premixed flame with different blend ratios and then used for the actual cases. 2D/3D simulations for the identified flames are performed using FGM and finite rate combustion models. Numerical results from both these models are compared with the available experimental data to understand FGM’s applicability. The results show that the FGM model performs reasonably well for pure hydrogen and hydrogen blended flames.
Influence of Yawed Wind Flow on the Blade Forces/Bending Moments and Blade Elastic Torsion for an Axial-Flow Wind Turbine
Authors: Ahmadi Mohammad H. B. , Yang Zhiyin 
Published: September 2021

Abstract
Effects of yawed incoming flow on wind turbine blades forces and root bending moments (RBMs) are not fully understood. To advance our current understanding, numerical studies of a small-scale three-bladed horizontal axis wind turbine at TSR = 6.7 with yaw angles of zero and 45° have been carried out to examine the variations of blade and rotor loading due to the yawed incoming flow. An approach combining Large Eddy Simulation (LES) with Actuator Line Modelling (ALM) has been employed in the present study. The predicted phase-averaged blade forces reveal that the blade tangential force, in-plane RBM and power coefficient are much more sensitive to the upstream streamwise velocity variations and are much more strongly affected than the blade axial force, out-of-plane RBM and thrust coefficient. It also shows that for yawed incoming flows the blade axial force to the blade tangential force ratio fluctuates significantly during one rotor revolution, resulting in large variations of the blade elastic torsion and that the total blade force (magnitude and direction) undergoes a non-linear change in the circumferential and radial directions, which will likely lead to the reduction in the turbine operational life significantly, especially for long lightweight blades of large size wind turbines.
Modeling and Testing of a Novel Ultra-Low Temperature sCO2 Opposing Piston Expander
Authors: Schmitt Joshua , Nielson Jordan 
Published: September 2021

Abstract
Southwest Research Institute (SwRI) along with Thermal Tech Holdings (TTH) have modeled, built, and tested a piston expander for generating power from low temperature heat sources. The piston was developed with the goal of creating an engine that operates as a recuperated sCO2 Ericsson cycle. A cycle model based on fluid properties from REFPROP is applied for various hot and cold temperatures to demonstrate the potential of the novel expander to improve cycle efficiency. Cycle modeling results demonstrate the potential improvements in cycle efficiency when compared to the sCO2 Brayton cycle. Small-scale bench testing is used to validate the novel piston concept for achieving a sCO2 Ericsson cycle. The concept is scaled up to a full-sized, opposing piston cylinder that acts as an expander in the theoretical Ericsson cycle. Testing is performed on the full-scale piston cylinder for a variety of inlet temperatures and pressures. The full-scale tests are run continuously to track the transient effects. The results of the full-scale test are discussed. The expander piston cylinder test results show high temperatures at the outlet, better than the ideal sCO2 Brayton cycle, but less than an ideal recuperated sCO2 Ericsson cycle. Comparisons are made to demonstrate the projected cycle efficiency improvements over a sCO2 Brayton cycle.
Gas Turbine Based Fuel Cell Vehicle Charging Station
Authors: Ganiger Manjush , Pandey Maneesh , Wagh Rahul , Govindasamy Rakesh 
Published: September 2021

Abstract
Hydrogen as fuel for transportation sector is going to play a prominent role when it comes combating the climate change, as its only by-products are heat and water. Rapid surge in adoption rate for fuel cell vehicle (FCV) could be driven by improvements in fuel cell technology, as well as rise in number of Fuel Cell Vehicle Charging Station (FCVCS).
This paper explores how a gas turbine from the Baker Hughes™ portfolio can be used to create a circular economy model for hydrogen fueling stations. Solid Oxide Electrolyzer (SOE) and carbon capture unit are the two prime components that are integrated to the gas turbine. The SOE unit, powered by the gas turbine, generates hydrogen for refueling the FCVs and to use for itself as a blended fuel, bringing down the carbon footprint.
Proposed FCVCS solution can refuel about 250 FCVs in half a day of operation (50% power split). Economic analysis shows that the solution is lucrative with attractive return on investment. The solution is flexible to incorporate Power-to-X conversions. Modular nature of the solution makes it easy to implement in city limits as well as in remote locations, along the highways, where grid availability is a challenge.
Physical Modal for Acoustic Resonance Based on the Circular Cavity Structure in the Compressor
Authors: Fengtong Zhao , Jianfei Chen , Mingsui Yang , Yundong Sha , Xiaochi Luan 
Published: September 2021

Abstract
On the basis of the rectangular cavity plate model, the Parker resonance phenomenon is investigated by using the present calculation method, which verifies the effectiveness of the numerical calculation method adopted in the paper. Acoustic resonance occurs in the multistage compressor. The acoustic resonance frequency will be locked in a specific range which presents no variation in the rotating speed. The propagation status of the sound source of the acoustic resonance frequency should be from back to forward with a helical shape. The research method of the characteristics and mechanism of the acoustic resonance is proposed based on the annular cavity structure with the numerical simulation. The calculation models of the flow field and the sound field are established. The criterion of the sound resonating with the cavity and the characteristic condition when acoustic resonance occurred in the annular cavity structure is confirmed. The theoretical model of the acoustic resonance which is developed in the paper will be useful for the the three-dimensional model investigation into the acoustic resonance in the compressor, which can provide the better exhibition of the coupling relationship between the acoustic mode in the cavity and the vibration mode of the structure when the acoustic resonance occurs.
Constituent and Ply Level Understanding of Electrical Resistance in Si-Containing SiC/SiC Composites
Authors: El Rassi Joseph , Morscher Gregory N. 
Published: September 2021

Abstract
Electrical resistance, also known as direct current potential drop (DCPD), has been demonstrated as an enabling means to monitor damage evolution in SiC-based ceramic matrix composites. For laminate composites, it has become apparent that the location and orientation of SiC fibers, free Si and in some cases insertion of C rods can greatly affect the measured resistance. In addition, the nature of crack growth through the different plies which consist of different constituents will have different effects on the change in resistance. Therefore, both experimental and modeling approaches as to the resistance and change in resistance for different laminate architectures based on the nature of constituent content and orientation are needed to utilize and optimize electrical resistance as a health-monitoring technique. In this work, unidirectional and cross-ply laminate composites have been analyzed using a ply-based electrical model. Based on a ply-level circuit model, the change in resistance was modeled for damage development. It is believed that this can serve as a basis for tailoring the architecture/constituent content to create a “smarter” composite.
Association Between Inspiratory Muscle Function and Balance Ability in Older People: A Pooled Data Analysis Before and After Inspiratory Muscle Training
Authors: Ferraro Francesco V. , Gavin James P. , Wainwright Thomas W. , McConnell Alison K. 
Published: September 2021

Inspiratory muscle training (IMT) improved balance ability and respiratory muscle function in healthy older adults. The current study is a retrospective analysis to explore the relationship between inspiratory muscle function, balance ability, and adaptation to IMT. All participants (total = 129; IMT = 60; age range = 65–85 years) performed inspiratory and balance assessments, including the mini-balance evaluation system test, maximal inspiratory pressure, and peak inspiratory flow tests. Baseline inspiratory muscle function was positively related to balance ability (p < .05), and IMT-induced improvements in inspiratory function (23.3% in maximal inspiratory pressure, 8.0% in peak inspiratory flow rate, 14.9% in maximal peak inspiratory power) were related to improvements in balance (10.6% in mini-balance evaluation system test), with the greatest improvements (17.0%) observed in the oldest participants (76–85 years old,p < .05). In conclusion, with or without IMT, positive associations between inspiratory function and balance ability exist, with greater improvements in inspiratory muscle function related to greater improvements in balance ability.
Shape of the OGTT glucose response curve: relationship with β-cell function and differences by sex, race, and BMI in adults with early type 2 diabetes treated with metformin
Authors: Utzschneider Kristina M , Younes Naji , Rasouli Neda , Barzilay Joshua I , Banerji Mary Ann , Cohen Robert M , Gonzalez Erica V , Ismail-Beigi Faramarz , Mather Kieren J , Raskin Philip , Wexler Deborah J , Lachin John M , Kahn Steven E 
Published: September 2021

IntroductionThe shape of the glucose curve during an oral glucose tolerance test (OGTT) reflects β-cell function in populations without diabetes but has not been as well studied in those with diabetes. A monophasic shape has been associated with higher risk of diabetes, while a biphasic pattern has been associated with lower risk. We sought to determine if phenotypic or metabolic characteristics were associated with glucose response curve shape in adults with type 2 diabetes treated with metformin alone.Research design and methodsThis is a cross-sectional analysis of 3108 metformin-treated adults with type 2 diabetes diagnosed <10 years who underwent 2-hour 75 g OGTT at baseline as part of the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE). Insulin sensitivity (homeostasis model of insulin sensitivity, HOMA2-S) and β-cell function (early, late, and total incremental insulin and C peptide responses adjusted for HOMA2-S) were calculated. Glucose curve shape was classified as monophasic, biphasic, or continuous rise.ResultsThe monophasic profile was the most common (67.8% monophasic, 5.5% biphasic, 26.7% continuous rise). The monophasic subgroup was younger, more likely male and white, and had higher body mass index (BMI), while the continuous rise subgroup was more likely female and African American/black. HOMA2-S and fasting glucose did not differ among the subgroups. The biphasic subgroup had the highest early, late, and total insulin and C peptide responses (all p<0.05 vs monophasic and continuous rise). Compared with the monophasic subgroup, the continuous rise subgroup had similar early insulin (p=0.3) and C peptide (p=0.6) responses but lower late insulin (p<0.001) and total insulin (p=0.008) and C peptide (p<0.001) responses.ConclusionsBased on the large multiethnic GRADE cohort, sex, race, age, and BMI were found to be important determinants of the shape of the glucose response curve. A pattern of a continuously rising glucose at 2 hours reflected reduced β-cell function and may portend increased glycemic failure rates.Trial registration numberNCT01794143.
Incidence of ‘new-onset’ constipation and associated factors during lockdown due to the COVID-19 pandemic
Authors: Remes-Troche Jose Maria , Coss-Adame Enrique , Amieva-Balmori Mercedes , Velarde-Ruiz Velasco José Antonio , Gómez-Castaños Paulo César , Flores-Rendón Ricardo , Gómez-Escudero Octavio , Rodríguez-Leal María Celina , Durán-Rosas Cristina , Pinto-Gálvez Samanta Mayanin , Priego-Parra Bryan Adrián , Triana-Romero Arturo 
Published: September 2021

ObjectiveA minimum of physical activity and low liquid intake are factors that have been associated with constipation. The health emergency brought on by the COVID-19 pandemic has resulted in adopting behaviour, such as sheltering-in-place (less mobility) and dietary changes, creating a scenario we believe to be an adequate model for examining the appearance of symptoms of constipation and its associated factors.DesignA cross-sectional and descriptive study was conducted on an open population, applying an electronic survey (4 weeks after lockdown due to COVID-19 in Mexico) to evaluate demographic characteristics, physical activity, water and fibre intake, appearance of constipation symptoms (including stool consistency), and quality of life.ResultsOut of 678 subjects evaluated, 170 (25%, 95% CI: 21.7 to 28.4) developed symptoms of ‘new-onset’ constipation, with a significant decrease in the number of daily bowel movements (p<0.05) and stool consistency (p<0.05) during lockdown. Furthermore, in the ‘new-onset’ constipation population there was a higher proportion of subjects (79 (47%) of 170) who stopped exercising during the pandemic compared with the subjects who did not develop constipation symptoms (187 (37%) of 508, p=0.03, OR: 1.49, 95% CI: 1.0 to 2.1). The multivariate analysis (logistic regression) showed that female sex (p=0.001), water intake (p=0.039), and physical activity (p=0.012) were associated with ‘new-onset’ constipation.ConclusionsIn our study on an open population in Mexico, we found that one-fourth of the population developed ‘new-onset’ constipation symptoms during the lockdown imposed due to the COVID-19 pandemic. A reduction of physical activity and less water consumption were associated factors.
Route of oxytocin administration for preventing blood loss at caesarean section: a systematic review with meta-analysis
Authors: Torloni Maria Regina , Siaulys Monica , Riera Rachel , Martimbianco Ana Luiza Cabrera , Pacheco Rafael Leite , Latorraca Carolina de Oliveira Cruz , Widmer Mariana , Betran Ana Pilar 
Published: September 2021

ObjectivesAssess the effects of different routes of prophylactic oxytocin administration for preventing blood loss at caesarean section (CS).DesignSystematic review and meta-analysis.MethodsMedline, EMBASE, CINAHL, Cochrane Library, BVS, SciELO and Global Index Medicus were searched through 24 May 2020 for randomised controlled trials (RCTs) comparing different routes of prophylactic oxytocin administration during CS. Study selection, data extraction and quality assessment were conducted by two investigators independently. We pooled results in fixed effects meta-analyses and calculated average risk ratio (RR), mean difference (MD) and 95% CI. We used GRADE to assess the overall quality of evidence for each outcome.ResultsThree trials (180 women) were included in the review. All studies compared intramyometrial (IMY) versus intravenous oxytocin in women having prelabour CS. IMY compared with intravenous oxytocin administration may result in little or no difference in the incidence of postpartum haemorrhage (RR 0.14, 95% CI 0.01 to 2.70; N=100 participants; 1 RCT), hypotension (RR 1.00, 95% CI 0.29 to 3.45; N=40; 1 RCT), headache (RR 3.00, 95% CI 0.13 to 69.52; N=40; 1 RCT) or facial flushing (RR 0.50, 95% CI 0.05 to 5.08; N=40; 1 RCT); IMY oxytocin may reduce nausea/vomiting (RR 0.13, 95% CI 0.02 to 0.69; N=140; 2 RCTs). We are very uncertain about the effect IMY versus intravenous oxytocin on the need for additional uterotonics (RR 0.82; 95% CI 0.25 to 2.69; N=140; 2 RCTs). IMY oxytocin may reduce blood loss slightly (MD −57.40 mL, 95% CI −101.71 to −13.09; N=40; 1 RCT).ConclusionsThere is limited, low to very low certainty evidence on the effects of IMY versus intravenous oxytocin at CS for preventing blood loss. The evidence is insufficient to support choosing one route over another. More trials, including studies that assess intramuscular oxytocin administration, are needed on this relevant question.PROSPERO registration numberCRD42020186797.
Effect of first-line antifungal treatment on ocular complication risk inCandidaor yeast blood stream infection
Authors: Hautala Nina , Köykkä Hannu , Siiskonen Mira , Saari Juho , Kauranen Jari , Hautala Timo 
Published: September 2021

ObjectivesOcular candidiasis (OC) can complicateCandidabloodstream infection (BSI). Antifungal treatment improves the prognosis of patients with BSI, but the effects of choice and timing of first-line medication on OC risk are incompletely understood. We explored the early treatments, risk factors and ocular presentations inCandidaBSI.Methods and analysisAll patients (n=304) withCandidaBSI during 2008–2017 at Oulu University Hospital were included. Those patients in whom clinical condition was appropriate for ocular examination (OE), including biomicroscopy (n=103), were carefully analysed by ophthalmologists. Criteria for patient selection were considered.Candidaand yeast species, antifungal medications, echocardiography, underlying diseases and clinical properties of the patients withCandidaBSI were analysed.ResultsClinical condition in 103 patients had been considered appropriate for OE. OC was diagnosed in 33 of the 103 patients.Candida albicanswas the most common finding (88%) in OC. Patients in intensive care, alcohol-related conditions or poor prognosis were less frequently examined. Persistent candidemia increased the risk of OC. Chorioretinitis and endophthalmitis were diagnosed in 94% and 48% of the patients with OC, respectively. Any early antifungal treatment decreased the endophthalmitis risk. Echinocandin lowered the OC risk in those with central venous catheters (CVCs) or abdominal malignancy.ConclusionCritical condition of patients withCandidaBSI affects the selection and results of OE. OC was associated withC. albicansBSI especially among those with persistent candidemia, CVC or abdominal malignancy. Any early antifungal treatment reduced endophthalmitis risk. Early echinocandin treatment may reduce the risk of OC in selected patients.