bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Structure of Ceramic Substrate to Reduce the Critical Electric Field in High Voltage Power Modules
Authors: Yan Feifei , Wang Laili , Gan Yongmei , Li Kaixuan , Zhang Boya 
Published: February 2022

Abstract
The blocking voltage level of silicon carbide (SiC) can reach 10–25 kV, which will significantly increase the power density and capacity of power modules. However, high voltage can induce a high electric field, increase the risk of partial discharge (PD), and threaten the insulation reliability. This paper focuses on the triple points between the metal electrode, silicone gel, and ceramic in power modules. The influencing factors of the electric field at different triple points are fully analyzed. PD experiments are performed and the results show that the interface between silicone gel and ceramic is a weak area of insulation. Therefore, this paper demonstrates that area of weak insulation and high electric field meet at the triple point. To solve this problem, a new structure of the ceramic substrate is proposed, which isolates the interface area from the high electric field. At the same time, the new structure can significantly reduce the high electric field reinforcement.
A Direct Numerical Simulation Investigation of the One-Phase Flow in a Simplified Emulsification Device
Authors: Olad Peyman , Crialesi Esposito Marco , Brandt Luca , Innings Fredrik , Håkansson Andreas 
Published: February 2022

Abstract
More detailed investigation of the flow inside emulsification devices, e.g., High-pressure homogenizers (HPHs) helps the industry to broaden the fundamental understanding of the working principle of these machines which in turn will pave the road to increase the breakup efficiency of emulsification processes. Direct numerical simulation (DNS) is not deemed as a practical method in industry due to the high computational cost and time. This study is the first DNS carried out on a model of an emulsification device model. The goal of this study is to set a benchmark for future CFD investigations using industrially favorable tools (RANS, LES, etc.). A scale-up model HPH is designed and the results show a successful modeling of the flow field mimicking the flow behavior inside a typical HPH.
Validation of the Porous Medium Approximation for Hydrodynamics Analysis in Compact Heat Exchangers
Authors: Zhu Qingzi , Pishahang Mehdi , Caccia Mario , Kelsall Colin C. , LaPotin Alina , Sandhage Kenneth H. , Henry Asegun 
Published: February 2022

AbstractCompact heat exchangers (HXs) have gained attention in recent years in various fields such as solar and nuclear power generation, oil and gas, and refrigeration due to their low cost, high power density, and robustness in high-pressure and/or high-temperature environments. However, the large difference between a compact HX's overall dimensions (∼m) and the much smaller scale of its channels (∼mm) makes it challenging to model the entire HX at once, due to computational limitations. In this work, we treat the channeled region of a compact HX as a porous medium (PM) to circumvent the need to model/mesh each individual channel. This allows us to simulate the entire HX, including both the header and channeled regions while maintaining the computational cost at a practical level. Although the porous medium approach has been used to model heat exchangers, its validity is still questionable because (1) the resistance coefficients are heavily data-based and thus difficult to be applied to new heat exchangers and (2) the validation has been focused on matching the overall pressure drop in the channel region, which does not address whether such model can predict detailed pressure and velocity field. For the first time, this work addresses under what circumstances and with what uncertainty does the PM approach work for hydrodynamics modeling in compact HXs. By answering these questions, we introduce the PM approach as a powerful tool for HX hydrodynamics modeling that can predict not only the overall pressure drop but also the detailed pressure and velocity distributions.
Investigation of the Flow Instabilities of a Low Specific Speed Pump Turbine Part 1: Experimental and Numerical Analysis
Authors: Deniz Sabri , Del Rio Armando , von Burg Martin , Tiefenthaler Manuel 
Published: February 2022

Abstract
This is the first part of a two-part paper focusing on the flow instabilities of pump turbines. In this first part, results of the experiments and computational fluid dynamics (CFD) simulations of the research carried out on a low specific speed model pump turbine at HSLU (Lucerne University of Applied Sciences) Switzerland are presented. The requirements of a stable and reliable pump turbine operation, under continuously expanding operating ranges, challenge the hydraulic design and demand new developments. This paper presents the results of experimental (model pump turbine at the test rig) and numerical (CFD) investigations of the pump turbine instabilities of a low specific speed (nq = 25) pump turbine in the turbine operating mode. Four-quadrant characteristics of a low specific speed pump turbine with two similar runners differentiating in the size (diameter) are measured. Testing of both runners with the same guide vane system provided information about the effects of the increased vaneless space on the pump turbine performance and stability. A CFD methodology is developed by applying several turbulence models to accurately predict the characteristics of the reversible pump turbines in the S-shaped region (speed no load conditions) as well as to analyze the flow features especially at off-design conditions. This CFD model is validated against the experimental data at 6 deg and 18 deg guide vane openings in turbine operating mode. Using the data of the unsteady pressure measurements and detailed investigation of unstable ranges on the pump turbine characteristics, flow instabilities in the low-specific speed model pump turbine are analyzed. Relevant frequencies such as rotating stall, steady and unsteady vortex formations are determined.
Investigation of the Flow Instabilities of a Low Specific Speed Pump Turbine Part 2: Flow Control With Fluid Injection
Authors: Deniz Sabri , von Burg Martin , Tiefenthaler Manuel 
Published: February 2022

Abstract
This is the second part of a two-part paper focusing on the flow instabilities of low-specific speed pump turbines. In this part, results of the flow control application with fluid injection in the vaneless space for suppressing the flow instabilities of a model pump turbine in turbine mode operation at HSLU (Lucerne University of Applied Sciences) Switzerland are presented. Using the experimental data and CFD results, the onset and development of flow instabilities are explored in the first part of this paper. Based on these analyses, a flow control technology using injection of fluid in the vaneless space of the model pump turbine is implemented in order to suppress the flow instabilities and, thereby, to extend the operating range. Through use of an external energy source, air and water injection are applied with discrete nozzles that are circumferentially distributed in the vaneless space. The S-shaped pump turbine characteristics in turbine operating mode are modified so that the slope at speed no load conditions is no more positive meaning an improvement in the stability behavior. To the best of our knowledge, this is the first successful application of flow control with fluid injection in the vaneless space of pump turbines. Fluid injection is applied at two different guide vane openings. The analysis of the unsteady pressure data indicates that fluid injection in the vaneless space suppresses the flow instability such as rotating stall. Moreover, the water injection turns out to be more effective than the air injection for modifying the slope of the pump turbine characteristics.
Multiphase Flows in Plate and Shell Heat Exchangers
Authors: Costa M. O. B. , Beckedorff L. , de Paiva K. V. , Oliveira J. L. G. 
Published: February 2022

Abstract
Air–water and air–water–oil flows were analyzed in a complex channel prototype of a plate and shell heat exchanger (PSHE) with the aid of a fast camera. Air–water flows were characterized before the PSHE inlet port by electrical capacitance tomography (ECT). The effects of inlet pipe flow pattern (bubbly, stratified, or slug) and flow direction (upward or downward) on PSHE air–water flows were investigated. The resultant phase distribution within the PSHE channel was determined by imaging analysis. Instantaneous velocity fields projected on the channel frontal plane were obtained with particle image velocimetry (PIV) for the dispersed phase of bubbly flows. Stratified pipe flow pattern results in PSHE channel segregated flow. The thermal analysis of segregated flow patterns occurring in the hot and cold sides of a PSHE reveals that the countercurrent configuration may present worse heat transfer performance than the parallel one. PSHE multiphase flows are characterized by breakup phenomenon: the mixture among phases is intensified even if stratification occurs at the inlet port. Oil–water–air downward flows are characterized by oil–water emulsion at the channel center and by water and air–water streams at the channel external part. Oil–water–air upward flows are characterized by air–water and oil–water emulsions at the channel center and by the water stream at the channel external part.
Combined Effects of the Turbulence and Interfacial Momentum Transfer on Two-Phase Turbulent Bubbly Flows
Authors: Aouadi Aroua , Bellakhal Ghazi , Chahed Jamel 
Published: February 2022

Abstract
The paper studies one-way and two-way coupling interactions between the liquid turbulence and bubbles' presence in bubbly jets. One-way coupling focuses on jet with low void fraction in which the bubbles have no significant effect on the hydrodynamic liquid fields in comparison to the single-phase jet. It sets out to model the interfacial momentum transfer identifying the turbulent contribution and its effect on the bubbles' dynamics and phase distribution. Two-way coupling considers jets with high void fractions where the liquid turbulence is altered by the bubbles which in turn influence the interfacial momentum transfers. This paper aims to improve the two-fluid model closures by implementing in computational fluid dynamics code a three-equation turbulence model and new interfacial momentum transfer closures. A benchmark of turbulence models combined with different interfacial exchange modeling is achieved to highlight the strong couplings between the interfacial forces, the phase distribution and the hydrodynamic fields of both phases.
Risk factors for epiretinal membrane in eyes with primary rhegmatogenous retinal detachment that received silicone oil tamponade
Authors: Pan Qintuo , Gao Zhiqiang , Hu Xuting , Wu Qi , Zheng Jing Wei , Zhang Zong-Duan 
Published: February 2022

Background/aimsThis study investigated the risk factors for epiretinal membrane (ERM) in eyes with primary rhegmatogenous retinal detachment (RRD) that received silicone oil (SO) tamponade.MethodsThis retrospective analysis included 1140 patients (1140 eyes) with RRD who underwent primary vitrectomy and SO tamponade. The prevalence of ERM was estimated and possible risk factors (eg, type 2 diabetes, proliferative vitreoretinopathy (PVR), SO tamponade time (SOTT), photocoagulation, vitreous haemorrhage, choroidal detachment, cryotherapy and retinal tear size) were analysed via multiple logistic regression.ResultsThe prevalence of ERM was 12.3% (140/1140), and the accuracy of preoperative ERM diagnosis was 40.5%. Multivariate logistic regression analysis showed that risk factors for ERM in eyes with SO tamponade included preoperative PVR (OR=4.336, 95% CI 2.533 to 7.424, p<0.001), type 2 diabetes (OR=3.996, 95% CI 2.013 to 7.932, p<0.001), photocoagulation energy (OR=1.785, 95% CI 1.306 to 2.439, p<0.001) and SOTT (OR=1.523, 95% CI 1.261 to 1.840, p<0.001). No statistically significant associations were observed between the incidence of ERM and other risk factors. Preoperative PVR showed the strongest association with risk of ERM. The risk of ERM was positively associated with SOTT, photocoagulation energy and preoperative PVR grade.ConclusionIn eyes with RRD that received SO tamponade, the prevalence of ERM was 12.3%, while the accuracy of preoperative ERM diagnosis was low. Preoperative PVR, type 2 diabetes, photocoagulation energy and SOTT were the main risk factors for ERM.
Better outcomes from exercise-related out-of-hospital cardiac arrest in males and in the young: findings from the Swedish Registry of Cardiopulmonary Resuscitation
Authors: Frisk Torell Matilda , Strömsöe Anneli , Herlitz Johan , Claesson Andreas , Rawshani Araz , Borjesson Mats 
Published: February 2022

BackgroundSurvival from out-of-hospital cardiac arrest (OHCA) is higher if the arrest is witnessed and occurs during exercise, however, there is contradicting data on prognosis with regards to sex and age. The purpose of this study was to compare the outcomes and circumstances of exercise-related OHCA in different age groups and between sexes in a large unselected population.MethodsData from exercise-related OHCAs reported to the Swedish Registry of Cardiopulmonary Resuscitation from 2011 to 2014 and from 2016 to 2018 were analysed. All cases of exercise-related OHCA in which emergency medical services attempted resuscitation were included. The primary outcome was survival to 30 days.ResultsIn total, 635 cases of exercise-related OHCA outside of the home were identified. The overall 30-day survival rate was 44.5% with highest survival rate in the age group 0–35 years, compared with 36–65 years and >65 years (59.6% vs 46.0% and 40.4%, p=0.01). A subgroup analysis of 0–25 years showed a survival rate of 68.8%. Exercise-related OHCA in females (9.1% of total) were witnessed to a lower extent (66.7% vs 79.6%, p=0.03) and median time to cardiopulmonary resuscitation (CPR) was longer (2.0 vs 1.0 min, p=0.001) than in males. Females also had lower rates of ventricular fibrillation (43.4% vs 64.7%, p=0.003) and a lower 30-day survival rate (29.3% vs 46.0%, p=0.02).ConclusionIn exercise-related OHCA, younger victims have a higher survival rate. Exercise-related OHCA in females was rare, however, survival rates were lower compared with males and partly explained by a lower proportion of witnessed events, longer time to CPR and lower frequency of a shockable rhythm.
Social networks, high-risk anal HPV and coinfection with HIV in young sexual minority men
Authors: Fujimoto Kayo , Nyitray Alan G , Kuo Jacky , Zhao Jing , Hwang Lu-Yu , Chiao Elizabeth , Giuliano Anna R , Schneider John A , Khanna Aditya 
Published: February 2022

ObjectivesYoung sexual minority men (SMM) exhibit a high prevalence and incidence of high-risk genotypes of human papillomavirus (hrHPV) anal infections and a confluence of a high prevalence of HIV and rectal STIs. Social determinants of health (SDOHs) are linked to social network contexts that generate and maintain racial disparities in HIV and STIs. A network perspective was provided to advance our knowledge of drivers of genotype-specific hrHPV infection and coinfection with HIV. The study also examined whether socially connected men are infected with the same high-risk HPV genotypes and, if so, whether this tendency is conditioned on coinfection with HIV.MethodsOur sample included 136 young SMM of predominantly black race and their network members of other races and ethnicities, aged 18–29 years, who resided in Houston, Texas, USA. These participants were recruited during 2014–2016 at the baseline recruitment period by network-based peer referral, where anal exfoliated cells and named social and sexual partners were collected. Exponential random graph models were estimated to assess similarity in genotype-specific hrHPV anal infection in social connections and coinfection with HIV in consideration of the effects of similarity in sociodemographic, sexual behavioural characteristics, SDOHs and syphilis infection.ResultsPairs of men socially connected to each other tend to be infected with the same hrHPV genotypes of HPV-16, HPV-45 and HPV-51 or HPV-16 and/or HPV-18. The tendency of social connections between pairs of men who were infected with either HPV-16 or HPV-18 were conditioned on HIV infection.ConclusionsNetworked patterns of hrHPV infection could be amenable to network-based HPV prevention interventions that engage young SMM of predominantly racial minority groups who are out of HIV care and vulnerable to high-risk HPV acquisition.
Relative increases in direct-to-consumer menthol ads following 2020 FDA guidance on flavoured e-cigarettes
Authors: Do Elizabeth K , O’Connor Katie , Diaz Megan C , Schillo Barbara A , Kreslake Jennifer M , Hair Elizabeth C 
Published: February 2022

ObjectiveTo examine potential changes in email and direct mail advertisements for flavoured e-cigarettes following the 2020 Food and Drug Administration (FDA) flavour guidance.MethodsDigital copies of e-cigarette advertisements were obtained from Mintel Comperemedia (November 2019–May 2020) and coded for the presence of flavours. Χ2tests were used to determine changes in the prevalence of email and direct mail advertisements for e-cigarettes with menthol, non-menthol and no flavours.ResultsFollowing FDA guidance, the relative proportion of menthol-flavoured e-cigarette advertisements sent via email significantly increased from 22.5% to 52.2%. No changes were found for e-cigarette advertisements mentioning no flavours, nor non-menthol-flavoured e-cigarettes, sent via email or direct mail.ConclusionsThe 2020 FDA flavour guidance was followed by an increased proportion of direct-to-consumer email advertisements of menthol-flavoured e-cigarette products.
General relativity and topological string duality through Penrose–Ward transform
Authors: Hristov J. 
Published: February 2022

AbstractThis paper discusses the relation between topological M-theory, self-dual Yang–Mills and general relativity. We construct a topological membrane field action from Witten’s cubic string field theory, which reduces to topological Yang–Mills on a one-parameter family of conifolds. It turns out that this can be interpreted as the twistor space of the four-dimensional Lagrangian submanifold M for large momenta. From the viewpoint of the target, we find that A-model and B-model onMunify in the topological membrane theory through the Penrose–Ward transform. The partition function is constructed and it is shown that, in the weak-coupling regime, it is equal to the partition function of Donaldson-Witten theory. Additionally, homological mirror symmetry, background independence as well as role of knot cobordisms as topological two-branes is discussed. It is outlined that all types of Floer homology are part of the topological membrane theory. Additionally, we find evidence that in the non-perturbative regime, the partition function of the membrane field action and that of the partially twisted (2,0) SU(N) superconformal field theory on the worldvolume of N topological fivebranes must coincide.
Discriminating the heavy jet production mechanisms in associated Z + heavy flavor events at the LHC
Authors: Baranov S. P. , Martinez A. Bermudez , Jung H. , Lipatov A. V. , Malyshev M. A. , Monfared S. Taheri 
Published: February 2022

AbstractWe reconsider the associated Z boson and charm or beauty jet production at the LHC by paying special attention to the formation dynamics of heavy jets. Two different approaches are studied: first one, where heavy quarks are produced in the hard scattering subprocesses, implemented in the Monte-Carlo generator pegasus, and another method, where the hard scattering is calculated at NLO with MadGraph5_aMC@NLO and TMD parton shower is included (implemented in the Monte-Carlo generator Cascade3). We compare the predictions obtained in both schemes with latest experimental data for associated $$Z + b$$

Z
+
b

production cross sections and the relative production rate $$\sigma (Z + c)/\sigma (Z + b)$$

σ
(
Z
+
c
)
/
σ
(
Z
+
b
)

collected by the ATLAS and CMS Collaborations at $$\sqrt{s} = 13$$

s

=
13

TeV. We introduce two kinematic observables (denoted as $$z_b$$

z
b

and $$p_T^\mathrm{rel}$$

p
T
rel

) which can be used to discriminate between the heavy jet production mechanisms. Using these variables we trace the shape of the simulated b-jet events and recommend that these observables be taken into consideration in the forthcoming experimental analyses.
Design of neuro-swarming computational solver for the fractional Bagley–Torvik mathematical model
Authors: Guirao Juan L. G. , Sabir Zulqurnain , Raja Muhammad Asif Zahoor , Baleanu Dumitru 
Published: February 2022

AbstractThis study is to introduce a novel design and implementation of a neuro-swarming computational numerical procedure for numerical treatment of the fractional Bagley–Torvik mathematical model (FBTMM). The optimization procedures based on the global search with particle swarm optimization (PSO) and local search via active-set approach (ASA), while Mayer wavelet kernel-based activation function used in neural network (MWNNs) modeling, i.e., MWNN-PSOASA, to solve the FBTMM. The efficiency of the proposed stochastic solver MWNN-GAASA is utilized to solve three different variants based on the fractional order of the FBTMM. For the meticulousness of the stochastic solver MWNN-PSOASA, the obtained and exact solutions are compared for each variant of the FBTMM with reasonable accuracy. For the reliability of the stochastic solver MWNN-PSOASA, the statistical investigations are provided based on the stability, robustness, accuracy and convergence metrics.
Effect of Graded Levels of Dietary Emamectin Benzoate on Immunity, Enzyme Activity, and Withdrawal Period in Labeo rohita Juveniles (Hamilton, 1822)
Authors: Choudhary Pushpa , Swain Priyabrat , Das Rakesh , Sahoo Satya Narayan , Das Krushna Chandra , Patil Prasanna Kumar , Mishra Sudhansu Sekhar 
Published: February 2022

This study was conducted to evaluate the effect of dietary emamectin benzoate (EB) levels on immune responses, serum enzyme activities, and retention of EB in muscle tissue to establish the withdrawal period in rohu, Labeo rohita juveniles (avg. wt.

18
±
0.11

g). To ascertain this, 450 healthy L. rohita juveniles were fed with EB in graded doses viz., at 50 (1x), 125 (2.5x), 250 (5x), and 375 (7.5x) μg kg-1 of fish biomass day-1, respectively, in triplicate for 21 days through a basal feed. Upon completion of 21 days, the same experimental fish were fed with basal feed (without EB) for another 14 days to measure the retention of EB in the muscle tissue. Each 7-day interval, five fish were randomly sampled. The results showed that respiratory burst activity, myeloperoxidase activity, bacterial haemagglutination, and haemolysis activities were improved significantly (

p
<
0.05

) in 1x and 2.5x dose fed group from 7th day onwards until 14th day. Few selected enzyme activities viz., LDH and ALP were found to be significantly (

p
<
0.05

) high in the fish fed with EB at 5x and 7.5x dose compared to 1x. The LC-MS/MS study of the experimental fish discloses that EB was retained in muscle tissue at a dose-dependent manner and significantly (

p
<
0.05

) lowest level (

0.341
±
0.03

ppb) was retained in the fish fed with 1x dose of EB. Hence, 1x dose of EB may be adhered to treat L. rohita juveniles through feed with 14 days of withdrawal period.