bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Analysis of Heat Transfer Enhancement in a Micro-Channel Due to Mechanical Stirrers
Authors: Sreejith M. , Chetan S. , Khaderi S. N. 
Published: May 2020

Abstract
Using two-dimensional numerical simulations of the momentum, mass, and energy conservation equations, we investigate the enhancement of heat transfer in a rectangular micro-fluidic channel. The fluid inside the channel is assumed to be stationary initially and actuated by the motion imparted by mechanical stirrers, which are attached to the bottom of the channel. Based on the direction of the oscillation of the stirrers, the boundary conditions can be classified as either no-slip (when the oscillation is perpendicular to the length of the channel) or periodic (when the oscillation is along the length of the channel). The heat transfer enhancement due to the motion of the stirrers (with respect to the stationary stirrer situation) is analyzed in terms of the Reynolds number (ranging from 0.7 to 1000) and the Peclet number (ranging from 10 to 100). We find that the heat transfer first increases and then decreases with an increase in the Reynolds number for any given Peclet number. The heat transferred is maximum at a Reynolds number of 20 for the no-slip case and at a Reynolds number of 40 for the periodic case. For a given Peclet and Reynolds number, the heat flux for the periodic case is always larger than the no-slip case. We explain the reason for these trends using time-averaged flow velocity profiles induced by the oscillation of the mechanical stirrers.
Thermodynamic Analysis for Supercritical Carbon Dioxide Brayton Cycle by Considering Both Thermal Efficiency and Cooler Area
Authors: Hu Peng , Jiang Yi-Ran , Zhang Gao-Wei , Miao Zhen 
Published: May 2020

Abstract
The performances of the supercritical carbon dioxide (sCO2) Brayton cycle with the recuperator were investigated by the simulation method. Evaluation criteria were proposed for system performance optimization. The calculation and analysis of the system thermal efficiency and the length of the cooler were performed. The effects of the inlet and outlet pressure of the expander, the heat transfer coefficient and the logarithmic mean temperature difference (LMTD) on the system thermal efficiency and the length of the cooler were investigated. The system thermal efficiency has a peak value with the increase of the expander inlet pressure. The peak value varies from 45% to 45.4% with different expander outlet pressures. The average heat transfer coefficient and the length of the cooler decrease with the increase of the inlet pressure, but the LMTD is on the contrary. When the expander inlet pressure is in the low-pressure stage (22–26 MPa), the thermal efficiency of the lower outlet pressure (8 MPa) is higher, which ranges from 44.3% to 45.4%. However, the length of the cooler is also larger (6.7–10.9 m). As the expander inlet pressure rises to the high-pressure stage (26–30 MPa), the higher outlet pressure (9.5 MPa) has a greater advantage in the thermal efficiency, and the range of efficiency is 44.7–45%. Similarly, the length of the cooler is the largest (4.5–8 m). Therefore, both the thermal efficiency and the length of the cooler should be fully considered in the design of the system operating conditions.
Experimental Investigation of Air-Source Heat Pump Heating System With a Novel Thermal Storage Refrigerant-Heated Panel
Authors: Shao Suola , Zhang Huan , You Shijun , Wang Yaran 
Published: May 2020

Abstract
In response to the triple crisis of energy–environment–economy (3Es), the air-source heat pump (ASHP) system is considered to be one of the most feasible candidates to upgrade the traditional high emission heating solutions. In this paper, a novel thermal storage refrigerant-heated panel (RHP) is proposed for the ASHP heating system. Experiments were conducted in a climate chamber to test the heating and defrosting performance of the system, the thermal performance of the RHP, the system energy efficiency, and the system economic feasibility. The results show that the heat flux of the RHP is as high as 625.5 W/m2 at a condensation temperature of 40 °C and an outdoor air temperature of −7 °C. Meanwhile, the system is demonstrated to be reliable and competitive with efficient thermal stability in heating conditions and comfortable indoor thermal in defrosting conditions. The coefficient of performance (COP) ranges from 2.2 to 4.0 when the outdoor air temperature changes from −12 °C to 7 °C in the tests. Meanwhile, the initial capital cost and the total annual cost of the proposed system are 430 USD and 203.1 USD, respectively, which is competitive in the distracted heating systems.
Physics-Informed Neural Networks for Missing Physics Estimation in Cumulative Damage Models: A Case Study in Corrosion Fatigue
Authors: Dourado Arinan , Viana Felipe A. C. 
Published: May 2020

AbstractWe present a physics-informed neural network modeling approach for missing physics estimation in cumulative damage models. This hybrid approach is designed to merge physics-informed and data-driven layers within deep neural networks. The result is a cumulative damage model in which physics-informed layers are used to model relatively well understood phenomena and data-driven layers account for hard-to-model physics. A numerical experiment is used to present the main features of the proposed framework. The test problem consists of predicting corrosion-fatigue of an Al 2024-T3 alloy used on panels of aircraft wings. Besides cyclic loading, panels are also subjected to saline corrosion. In this case, physics-informed layers implement the well-known Walker model for crack propagation, while data-driven layers are trained to compensate the bias in damage accumulation due to the corrosion effects. The physics-informed neural network is trained using full observation of inputs (far-field loads, stress ratio, and a corrosivity index defined per airport) and very limited observation of outputs (crack length at inspection for only a small portion of the fleet). Results show that the physics-informed neural network is able to learn how to compensate the missing physics of corrosion in the original fatigue model. Predictions from the hybrid model can be used in fleet management, for example, to prioritize inspection across the fleet or forecast ahead of time the number of planes with damage above a threshold.
A General Modeling Methodology for the Quasistatic Behavior of Spiral Torsion Springs
Authors: Munoz-Guijosa Juan M. , Silva Alejandro , Alén-Cordero Cristina , Guzmán Álvaro 
Published: May 2020

Abstract
Due to their robustness, compactness, simplicity, and the possibility of nonlinear torque curves, spiral springs are being increasingly contemplated for industrial application. Recent manufacturing technologies and materials allow for the creation of spiral springs of various shapes and geometries able to provide the required torque curves. Modeling the behavior of this kind of springs is highly complex due to the strong nonlinearities arisen from large deflections and the possibility of coiling of strip length around the spring barrel or arbor. For this reason, up to our knowledge, existing models only provide design features such as deflection and torque curve for the simplest strip geometries, and fewer models supply, only if no strip coiling occurs, reactions at the strip-barrel and strip-arbor clampings. In addition, to our knowledge, just semi-empirical models for strip-barrel, -arbor and -strip contact forces or friction torques were available. In this work, we introduce a novel general, an analytical quasistatic model for the calculation of all the above spring characteristics for any length-dependent strip material and initial geometry and strip cross-sectional shape and for any barrel and arbor radii. The strip deflection curvatures are calculated minimizing the sum of elastic and gravitational potential energies under geometrical constraints associated with eventual strip coiling. Once the curvatures are calculated, the spring internal, contact, and reaction forces can be straightforwardly calculated by solving the elastica differential equations. Friction is taken into account by evaluating the contact conditions at the strip coiled sections.
Rotatability of the Floating Link on Multi-Loop Planar Linkages
Authors: Chan Cody Leeheng , Ting Kwun-Lon 
Published: May 2020

Abstract
This paper proposes a method to deal with the orientation uncertainty problem affected by joint clearances. To solve this problem, it is necessary to establish the theory of mobility of the floating link of multi-loop linkages. Since the theory of the mobility of floating link is yet complete, this paper provides a simple treatment to determine the rotatability between any two links, adjoined or not, in planar multi-loop linkages. The rotation angle of the floating link with respect to the reference link is defined so that there is no ambiguity in analyzing the rotation range of the floating link. Based on the joint rotation space (JRS) method, one may identify not only the branch formation but also the rotatability between any two links on each of the branches. It is a visualized method that reveals the rotation characteristic of multi-loop linkages. This paper demonstrates the rotation range of the floating link with respect to the reference link on six-bar Stephenson linkages, 2-degree-of-freedom (DOF). 7-bar linkages, and 3-DOF. Eight-bar parallel manipulators. This might be the first paper to deal with the rotatability of 3-DOF planar multi-loop linkages. This paper uses the method to predict the clearance-induced angle uncertainty of the 8-bar parallel manipulators, which determines the worst orientation error of the end-effector and fills up the void of the joint clearance uncertainty model proposed by Ting et al. (2017, “Clearance-Induced Position Uncertainty of Planar Linkages and Parallel Manipulators,” J. Mech. Rob., 9, p. 061001).
Forward Kinematic Analysis of Kinematically Redundant Hybrid Parallel Robots
Authors: Wen Kefei , Gosselin Clément M. 
Published: May 2020

Abstract
This paper focuses on the forward kinematic analysis of (6 + 3)-degree-of-freedom kinematically redundant hybrid parallel robots. Because all of the singularities are avoidable, the robot can cover a very large orientational workspace. The control of the robot requires the solution of the direct kinematic problem using the actuator encoder data as inputs. Seven different approaches of solving the forward kinematic problem based on different numbers of extra encoders are developed. It is revealed that five of these methods can produce a unique solution analytically or numerically. An example is given to validate the feasibility of these approaches. One of the provided approaches is applied to the real-time control of a prototype of the robot. It is also revealed that the proposed approaches can be applied to other kinematically redundant hybrid parallel robots proposed by the authors.
Physical Activity and Sport in Trans Persons Before and After Gender Disclosure: Prevalence, Frequency, and Type of Activities
Authors: López-Cañada Elena , Devís-Devís José , Valencia-Peris Alexandra , Pereira-García Sofía , Fuentes-Miguel Jorge , Pérez-Samaniego Víctor 
Published: May 2020

Background: This study describes the prevalence, frequency, and type of physical activity and sport (PAS) practiced by trans persons before and after their gender disclosure (GD). Methods: A face-to-face survey was administered to 212 Spanish trans persons, aged from 10 to 62 years old. McNemar and chi-square tests were used to determine significant differences. Results: About 75.5% of the trans persons in this study engaged in PAS and more than 50% did so ≥3 times/week, which is similar as in the general Spanish population. Participation was higher in trans men (78.7%) than trans women (72%). However, GD emerges as a key issue in characterizing trans persons’ PAS participation. A group of 14.5% of them stopped activity after GD. Participation in nonorganized PAS was higher than in organized PAS, and this difference is greater after GD because most participants gave up organized PAS in favor of nonorganized PAS. Trans persons preferred individual sports and activities than team sports before and after GD, and the top 3 activities were jogging, walking, and bodybuilding. Trans men participation was higher than trans women in team PAS, whereas individual PAS were equally practiced before and after GD. Participation in football, swimming, basketball, dancing, and volleyball declined after GD, whereas bodybuilding increased in trans men. Conclusions: The results show that the high involvement of trans persons coincides with strategies used to hide or conceal their gender identities when participating in PAS. A decrease in PAS participation is observed after GD probably because it is an acute potential period of anxiety, discrimination, and victimization caused by trans persons’ body exposure.
Prevalence and associated phenotypes of DUSP6, IL17RD and SPRY4 variants in a large Chinese cohort with isolated hypogonadotropic hypogonadism
Authors: Men Meichao , Wang Xinying , Wu Jiayu , Zeng Wang , Jiang Fang , Zheng Ruizhi , Li Jia-Da 
Published: May 2020

BackgroundFGF8-FGFR1 signalling is involved in multiple biological processes, while impairment of this signalling is one of the main reasons for isolated hypogonadotropic hypogonadism (IHH). Recently, several negative modulators of FGF8-FGFR1 signalling were also found to be involved in IHH, including DUSP6, IL17RD, SPRY2 and SPRY4. The aim of this study was to investigate the genotypic and phenotypic spectra of these genes in a large cohort of Chinese patients with IHH.MethodsA total of 196 patients with IHH were enrolled in this study. Whole-exome sequencing was performed to identify variants, which was verified by PCR and Sanger sequencing.ResultsFour heterozygous DUSP6 variants (p.S157I, p.R83Q, p.P188L and p.N355I) were found in six patients. Cryptorchidism, dental agenesis, syndactyly and blue colour blindness were commonly observed in patients with DUSP6 mutations. Six heterozygous IL17RD variants (p.P191L, p.G35V, p.S671L, p.A221T, p.I329M and p.I329V) were found in seven patients. Segregation analysis indicated that 100% (5/5) of probands inherited the IL17RD variants from their unaffected parents, and oligogenicity was found in 4/7 patients. One rare SPRY4 variant (p.T68S) was found in a female patient with Kallmann syndrome who also carried a PLXNA1 mutation.ConclusionOur study greatly enriched the genotypic and phenotypic spectra of DUSP6, IL17RD and SPRY4 in IHH. Mutations in DUSP6 alone seem sufficient to cause IHH in an autosomal dominant manner, whereas IL17RD or SPRY4 mutations may cause IHH phenotypes in synergy with variants in other IHH-associated genes.
Tablet and web-based audiometry to screen for hearing loss in adults with cystic fibrosis
Authors: Vijayasingam Anitha , Frost Emily , Wilkins Julie , Gillen Lise , Premachandra Presanna , Mclaren Kate , Gilmartin Desmond , Picinali Lorenzo , Vidal-Diez Alberto , Borsci Simone , Ni Melody Zhifang , Tang Wai Y , Morris-Rosendahl Deborah , Harcourt Jonny , Elston Caroline , Simmonds N J , Shah Anand 
Published: May 2020

IntroductionIndividuals with chronic lung disease (eg, cystic fibrosis (CF)) often receive antimicrobial therapy including aminoglycosides resulting in ototoxicity. Extended high-frequency audiometry has increased sensitivity for ototoxicity detection, but diagnostic audiometry in a sound-booth is costly, time-consuming and requires a trained audiologist. This cross-sectional study analysed tablet-based audiometry (Shoebox MD) performed by non-audiologists in an outpatient setting, alongside home web-based audiometry (3D Tune-In) to screen for hearing loss in adults with CF.MethodsHearing was analysed in 126 CF adults using validated questionnaires, a web self-hearing test (0.5 to 4 kHz), tablet (0.25 to 12 kHz) and sound-booth audiometry (0.25 to 12 kHz). A threshold of ≥25 dB hearing loss at ≥1 audiometric frequency was considered abnormal. Demographics and mitochondrial DNA sequencing were used to analyse risk factors, and accuracy and usability of hearing tests determined.ResultsPrevalence of hearing loss within any frequency band tested was 48%. Multivariate analysis showed age (OR 1.127; (95% CI: 1.07 to 1.18; p value<0.0001) per year older) and total intravenous antibiotic days over 10 years (OR 1.006; (95% CI: 1.002 to 1.010; p value=0.004) per further intravenous day) were significantly associated with increased risk of hearing loss. Tablet audiometry had good usability, was 93% sensitive, 88% specific with 94% negative predictive value to screen for hearing loss compared with web self-test audiometry and questionnaires which had poor sensitivity (17% and 13%, respectively). Intraclass correlation (ICC) of tablet versus sound-booth audiometry showed high correlation (ICC >0.9) at all frequencies ≥4 kHz.ConclusionsAdults with CF have a high prevalence of drug-related hearing loss and tablet-based audiometry can be a practical, accurate screening tool within integrated ototoxicity monitoring programmes for early detection.
Spherical electro-vacuum black holes with resonant, scalar Q-hair
Authors: Herdeiro Carlos A. R. , Radu Eugen 
Published: May 2020

AbstractThe asymptotically flat, spherical, electro-vacuum black holes (BHs) are shown to support static, spherical configurations of a gauged, self-interacting, scalar field, minimally coupled to the geometry. Considering a Q-ball type potential for the scalar field, we dub these configurations Q-clouds, in the test field approximation. The clouds exist under a resonance condition, at the threshold of (charged) superradiance. This is similar to the stationary clouds supported by Kerr BHs, which exist for a synchronisation condition, at the threshold of (rotational) superradiance. In contrast with the rotating case, however, Q-clouds require the scalar field to be massive and self-interacting; no similar clouds exist for massive but free scalar fields. First, considering a decoupling limit, we construct Q-clouds around Schwarzschild and Reissner–Nordström BHs, showing there is always a mass gap. Then, we make the Q-clouds backreact, and construct fully non-linear solutions of the Einstein–Maxwell-gauged scalar system describing spherical, charged BHs with resonant, scalar Q-hair. Amongst other properties, we observe there is non-uniqueness of charged BHs in this model and the Q-hairy BHs can be entropically preferred over Reissner–Nordström, for the same charge to mass ratio; some Q-hairy BH solutions can be overcharged. We also discuss how some well known no-hair theorems in the literature, applying to electro-vacuum plus minimally coupled scalar fields, are circumvented by this new type of BHs.
Airy minima in 4He +28Si elastic and inelastic scattering
Authors: Berezhnoy Yu. A. , Molev A. S. 
Published: May 2020

We present the results of the [Formula: see text]-matrix description of the [Formula: see text] elastic and inelastic scattering differential cross-sections between 40 and 240 MeV with allocation of Airy minima of various orders. The first-order Airy minima have been unambiguously identified in the differential cross-sections for elastic scattering and inelastic scattering to the first [Formula: see text] state of [Formula: see text] at energies [Formula: see text] MeV, and the second-order Airy minima — at [Formula: see text] MeV. The angular positions of these minima obey an inverse dependence on energy. The intensities of nuclear refraction and absorption also obey the same energy dependence.
Survival Differences in Men and Women With Primary Malignant Cardiac Tumor: An Analysis Using the Surveillance, Epidemiology and End Results (SEER) Database From 1973 to 2015
Authors: Antwi‐Amoabeng Daniel , Meghji Zahara , Thakkar Samarthkumar , Ulanja Mark B. , Taha Mohamed , Adalja Devina , Al‐Khafaji Jaafar , Gullapalli Nageshwara , Beutler Bryce D. , Boampong‐Konam Killian , Doshi Rajkumar 
Published: May 2020

Background

No data are available on sex disparities in prevalence and survival for primary malignant cardiac tumors (
PMCT
). This study aimed to compare male and female
PMCT
prevalence and long‐term survival rates.

Methods and Results

We utilized the Surveillance, Epidemiology, and End Results (
SEER
) 18 database from the National Cancer Institute for all
PMCT
s diagnosed between 1973 and 2015. From a total of 7 384 580 cases of cancer registered in
SEER
, we identified 327 men and 367 women with
PMCT
s. The majority (78%) of patients were white. Sarcoma was the most common type of
PMCT
in both men and women (≈60%). Individuals diagnosed with lymphoma exhibited better survival than those with other types of
PMCT
s. Men were diagnosed at a younger age than women; however, there was no significant difference in overall survival between the sexes. Men diagnosed with
PMCT
between the ages of 51 and 65 years demonstrated prolonged survival compared with those diagnosed at younger or older ages. There was no difference in survival rates among women based on age at diagnosis.

Conclusions

PMCT
s are rare in both men and women. Tumors tend to be diagnosed at an earlier age in men compared with women, but there is no sex disparity in survival rate. Sarcoma is the most common type of
PMCT
, and lymphoma is associated with the highest survival rate among both sexes.
Nonlethal Inhibition of Gut Microbial Trimethylamine N‐oxide Production Improves Cardiac Function and Remodeling in a Murine Model of Heart Failure
Authors: Organ Chelsea L. , Li Zhen , Sharp Thomas E. , Polhemus David J. , Gupta Nilaksh , Goodchild Traci T. , Tang W. H. Wilson , Hazen Stanley L. , Lefer David J. 
Published: May 2020

Background

Patients at increased risk for coronary artery disease and adverse prognosis during heart failure exhibit increased levels of circulating trimethylamine N‐oxide (
TMAO
), a metabolite formed in the metabolism of dietary phosphatidylcholine. We investigated the efficacy of dietary withdrawal of
TMAO
as well as use of a gut microbe‐targeted inhibitor of
TMAO
production, on cardiac function and structure during heart failure.

Methods and Results

Male C57
BLK
/6J mice were fed either control diet, a diet containing
TMAO
(0.12% wt/wt), a diet containing choline (1% wt/wt), or a diet containing choline (1% wt/wt) plus a microbial choline trimethylamine lyase inhibitor, iodomethylcholine (0.06% wt/wt), starting 3 weeks before transverse aortic constriction. At 6 weeks after transverse aortic constriction, a subset of animals in the
TMAO
group were switched to a control diet for the remainder of the study. Left ventricular structure and function were monitored at 3‐week intervals. Withdrawal of
TMAO
from the diet attenuated adverse ventricular remodeling and improved cardiac function compared with the
TMAO
group. Similarly, inhibiting gut microbial conversion of choline to
TMAO
with a choline trimethylamine lyase inhibitor, iodomethylcholine, improved remodeling and cardiac function compared with the choline‐fed group.

Conclusions

These experimental findings are clinically relevant, and they demonstrate that
TMAO
levels are modifiable following long‐term exposure periods with either dietary withdrawal of
TMAO
or gut microbial blockade of
TMAO
generation. Furthermore, these therapeutic strategies to reduce circulating
TMAO
levels mitigate the negative effects of dietary choline and
TMAO
in heart failure.