Miracle-dz/UniFAR-FTUs huggingface dataset:
Further contributions on the two-dimensional flow in a sudden expansion

Two-dimensional laminar flow of an incompressible viscous fluid through a channel with a sudden expansion is investigated. A continuation method is applied to study the bifurcation structure of the discretized governing equations. The stability of the different solution branches is determined by an Arnoldi-based iterative method for calculating the most unstable eigenmodes of the linearized equations for the perturbation quantities. The bifurcation picture is extended by computing additional solution branches and bifurcation points. The behaviour of the critical eigenvalues in the neighbourhood of these bifurcation points is studied. Limiting cases for the geometrical and flow parameters are considered and numerical results are compared with analytical solutions for these cases.
Exergy analysis of engines fuelled with biodiesel from high oleic soybeans based on experimental values

This study dealt with energy and exergy analyses of a John Deere 4045T diesel engine run with no. 2 diesel fuel, Soybean oil Methyl Ester (SME) and High-Oleic soybean oil Methyl Ester (HOME) at 1400 1/min. It was aimed at determining energy and exergy efficiencies, energy losses and exergy destructions of the combustion process and comparing exergetically the fuels used. The specific exergy of the fuels was calculated to be efuel,No.2 Diesel > efuel,HOME > efuel,SME, while energy (thermal) and exergy efficiencies were 40.5% and 37.8%, respectively. There were no statistically significant differences between the fuels based on the Tukey method.
Artificial intelligence-enabled electrocardiographic screening for left ventricular systolic dysfunction and mortality risk prediction

Background Left ventricular systolic dysfunction (LVSD) characterized by a reduced left ventricular ejection fraction (LVEF) is associated with adverse patient outcomes. We aimed to build a deep neural network (DNN)-based model using standard 12-lead electrocardiogram (ECG) to screen for LVSD and stratify patient prognosis. Methods This retrospective chart review study was conducted using data from consecutive adults who underwent ECG examinations at Chang Gung Memorial Hospital in Taiwan between October 2007 and December 2019. DNN models were developed to recognize LVSD, defined as LVEF <40%, using original ECG signals or transformed images from 190,359 patients with paired ECG and echocardiogram within 14 days. The 190,359 patients were divided into a training set of 133,225 and a validation set of 57,134. The accuracy of recognizing LVSD and subsequent mortality predictions were tested using ECGs from 190,316 patients with paired data. Of these 190,316 patients, we further selected 49,564 patients with multiple echocardiographic data to predict LVSD incidence. We additionally used data from 1,194,982 patients who underwent ECG only to assess mortality prognostication. External validation was performed using data of 91,425 patients from Tri-Service General Hospital, Taiwan. Results The mean age of patients in the testing dataset was 63.7 ± 16.3 years (46.3% women), and 8,216 patients (4.3%) had LVSD. The median follow-up period was 3.9 years (interquartile range 1.5–7.9 years). The area under the receiver-operating characteristic curve (AUROC), sensitivity, and specificity of the signal-based DNN (DNN-signal) to identify LVSD were 0.95, 0.91, and 0.86, respectively. DNN signal-predicted LVSD was associated with age- and sex-adjusted hazard ratios (HRs) of 2.57 (95% confidence interval [CI], 2.53–2.62) for all-cause mortality and 6.09 (5.83–6.37) for cardiovascular mortality. In patients with multiple echocardiograms, a positive DNN prediction in patients with preserved LVEF was associated with an adjusted HR (95% CI) of 8.33 (7.71 to 9.00) for incident LVSD. Signal- and image-based DNNs performed equally well in the primary and additional datasets. Conclusion Using DNNs, ECG becomes a low-cost, clinically feasible tool to screen LVSD and facilitate accurate prognostication.
The predictability of a flow which possesses many scales of motion

It is proposed that certain formally deterministic fluid systems which possess many scales of motion are observationally indistinguishable from indeterministic systems; specifically, that two states of the system differing initially by a small “observational error” will evolve into two states differing as greatly as randomly chosen states of the system within a finite time interval, which cannot be lengthened by reducing the amplitude of the initial error. The hypothesis is investigated with a simple mathematical model. An equation whose dependent variables are ensemble averages of the “error energy” in separate scales of motion is derived from the vorticity equation which governs two-dimensional incompressible flow. Solutions of the equation are determined by numerical integration, for cases where the horizontal extent and total energy of the system are comparable to those of the earth's atomsphere. It is found that each scale of motion possesses an intrinsic finite range of predictability, provided that the total energy of the system does not fall off too rapidly with decreasing wave length. With the chosen values of the constants, “cumulus-scale” motions can be predicted about one hour, “synoptic-scale” motions a few days, and the largest scales a few weeks in advance. The applicability of the model to real physical systems, including the earth's atmosphere, is considered. DOI: 10.1111/j.2153-3490.1969. tb00444.x
The Far Ultraviolet Spectroscopic Explorer Survey of O VI Absorption in and near the Galaxy

We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the O VI λλ1031. 926, 1037.617 absorption lines associated with gas in and near the Milky Way, as detected in the spectra of a sample of 100 extragalactic targets and two distant halo stars. We combine data from several FUSE Science Team programs with guest observer data that were public before 2002 May 1. The sight lines cover most of the sky above Galactic latitude |b| > 25°—at lower latitude the ultraviolet extinction is usually too large for extragalactic observations. We describe the details of the calibration, alignment in velocity, continuum fitting, and manner in which several contaminants were removed—Galactic H2, absorption intrinsic to the background target and intergalactic Lyβ lines. This decontamination was done very carefully, and in several sight lines very subtle problems were found. We searched for O VI absorption in the velocity range -1200 to 1200 km s-1. With a few exceptions, we only find O VI in the velocity range -400 to 400 km s-1; the exceptions may be intergalactic O VI. In this paper we analyze the O VI associated with the Milky Way (and possibly with the Local Group). We discuss the separation of the observed O VI absorption into components associated with the Milky Way halo and components at high velocity, which are probably located in the neighborhood of the Milky Way. We describe the measurements of equivalent width and column density, and we analyze the different contributions to the errors. We conclude that low-velocity Galactic O VI absorption occurs along all sight lines—the few nondetections only occur in noisy spectra. We further show that high-velocity O VI is very common, having equivalent width >65 mÅ in 50% of the sight lines and equivalent width >30 mÅ in 70% of the high-quality sight lines. The central velocities of high-velocity O VI components range from |vLSR| = 100 to 330 km s-1; there is no correlation between velocity and absorption strength. We discuss the possibilities for studying O VI absorption associated with Local Group galaxies and conclude that O VI is probably detected in M31 and M33. We limit the extent of an O VI halo around M33 to be <100 kpc [at a 3 σ detection limit of log N(O VI) ∼ 14.0]. Using the measured column densities, we present 50 km s-1 wide O VI channel maps. These show evidence for the imprint of Galactic rotation. They also highlight two known H I high-velocity clouds (complex C and the Magellanic Stream). The channel maps further show that O VI at velocities <-200 km s-1 occurs along all sight lines in the region l = 20°-150°, b < -30°, while O VI at velocities >200 km s-1 occurs along all sight lines in the region l = 180°-300°, b > 20°.
Experiments in Hearing

or speaking has had the experience of coming across a passage, a phrase, or a word in the writings of others which was so pat and appropriate in its use that it has caused him to say to himself, "Now I wish that I had said that ! " As I completed the work and joy of reading this book I thought of Robert Schumann, the German composer, writer, and music critic. Speaking through the mouth of Eusebius, one of his pen names, Schumann described his first meeting with the music of Chopin. His description of this thrilling moment follows. "Eusebius came in softly the other day. You know that ironic smile with which he tries to intrigue you. I was at the piano . Eusebius put a piece of music before us with these words, 'Hats off, gentlemen\p=m-\agenius ! ' " Since I cannot claim authorship of this encomium I humbly borrow it, para¬ phrase it, and use it here: "Hats off, gentlemen, in the presence of an otological genius ! " It is the feeling of this reviewer that this work of Georg von Bekesy stands supreme over the sum of all other work yet published in the field of the anatomy and the physiology of the processes of hearing. It is the integration into book form of all the work published by von Bekesy to date of publication. For this
Scattering of electromagnetic waves by a perfectly conducting cylinder with a thin lossy magnetic coating

We study the scattering interaction of electromagnetic (EM) waves with an infinite cylinder coated with a lossy dielectric material with frequency-dependent material properties. These properties are hypothetical, yet representative of a wide class of available materials. The monostatic and bistatic scattered widths (SW) are evaluated for the TM or TE polarization cases. These calculations require the use of algorithms to evaluate Bessel-Hankel functions of complex arguments. These algorithms are based on a continued fraction approach, which ensures stability of the recursion relations. The bistatic plots of the TM and TE scattering widths for the coated body are displayed in a convenient color-graded scale. The reductions in the scattering widths produced by this type of coating are determined in selected frequency bands and angular sectors, in both polarization cases. It is quantitatively shown how curvature and polarization shift the effectiveness band of the coating. The determined regions in which the SW are minimally affected are the most suitable for target identification purposes.
The Incidence of Hypothyroidism Following Hemithyroidectomy in a Tertiary Academic Center in Saudi Arabia

Background Hemithyroidectomy is a common procedure used to treat various benign and malignant conditions. It is often associated with complications, of which hypothyroidism is an underappreciated sequel. We sought to comprehend the rate and associated risk factors for developing hypothyroidism following hemithyroidectomy at King Abdulaziz University Hospital (KAUH). Methods In this retrospective study, we reviewed the medical records of all patients who had hemithyroidectomies for benign and malignant conditions between January 2008 and August 2022. Patients were analyzed for age, gender, body mass index (BMI), comorbidities, family history of thyroid disease, thyroid antibodies, and pre- and postoperative thyroid-stimulating hormone (TSH). Pre- and postoperative TSH levels were compared using the Wilcoxon signed-rank test. Results From 153 cases, 39 patients met the inclusion criteria; 31 (79.5%) were females. Seventeen (43.59%) patients developed biochemical hypothyroidism within two years following hemithyroidectomy; the majority (64.71%) of those with hypothyroidism developed it within the first six months. There was a significant increase in TSH levels following surgery (p < 0.001). Conclusion The overall incidence of hypothyroidism within two years of hemithyroidectomy is 43.59%; among those who developed hypothyroidism, the majority (64.71%) did so within the first six months. Thus, we strongly recommend continuous monitoring of TSH levels in the first six months, as it may aid in the decision to begin treatment before symptoms develop.
Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices.
An Empirical Analysis of the Aircraft Emissions by Operating from Scheduled Flights within the Domestic Market in Spain

Over the past 20 years, civil aviation has substantially reduced its environmental impact to augment sustainable transportation. In Spain, the domestic market has been habitually characterized by a few enterprises providing air transport services linked to scheduled flights on domestic corridors. Because of geographic diversity and the highly concentrated population characterizing this southern European country, many of them could not be supplied by alternative transport modes in terms of both time and distance by comparison with air transportation. For air quality monitoring from 139 national corridors, this paper aims to study related aviation emissions to conduct an economic analysis in terms of positive or negative externalities. For such purposes, the study focused on these domestic routes served by the five most important Spanish airports, specifically on the number of passengers transported from 2011 to 2020. Up to 10 aircraft types representing no more than 89% of regular operations on these flyways were subsequently identified. In addition, certain engine types also were selected as representatives to evaluate their emissions, depending on the great-circle distance in each route. The research findings, though particularly conditioned by aviation peculiarities of such a domestic market, point decisively to significant dependence upon emissions in connection with the seasonality of the demand and the concentration of flights with low occupancy indices from any one of them. Results suggest that airlines would benefit from operating turboprops instead of turbojets on selected routes, especially when oil prices are high. However, it is not always easy to find a balance between uncompromising economic profitability and effective fleet availability, since nowadays air transport undertakings tend to unify their fleets by using a few aircraft families, mostly powered by jet engines, apart from regional carriers.
Large-eddy simulation and Lagrangian stochastic modeling of passive scalar dispersion in a turbulent boundary layer

A large-eddy simulation (LES) with the dynamic Smagorinsky–Germano subgrid scale (SGS) model is used to study the passive scalar dispersion in a turbulent boundary layer. Instead of resolving the passive scalar transport equation, fluid particles containing scalar are tracked in a Lagrangian way. The Lagrangian velocity of each fluid particle is considered to have a large-scale part (directly computed by the LES) and a small-scale part. The movement of fluid elements containing scalar at a subgrid level is given by a three-dimensional Langevin model. The stochastic model is written in terms of SGS statistics at a mesh level. The results of the LES are compared with the wind-tunnel experiments of Fackrell and Robins (1982, Journal of Fluid Mechanics, 117, 1–26) and with the LES results of Sykes and Henn (1992, Atmospheric Environment A, 26, 3127–3144), who used a completely Eulerian approach with a non-dynamic SGS model. Our simulations predict the quantitative features of the experiments of Fackrell and Robins (1982, Journal Fluid Mechanics, 117, 1–26). Moreover, by using the Lagrangian approach, scalar fluxes are computed with no additional modeling assumptions and show good agreement with the experimental data. A classic mean-gradient model of the scalar flux is calculated from the computed results. The agreement between the directly computed fluxes and the classic mean-gradient model calculation is remarkable.
β-Cyclodextrin inclusion complexes of combined Moroccan Rosmarinus officinalis, Lavandula angustifolia and Citrus aurantium volatile oil: production optimization and release kinetics in food models

ABSTRACT A combined volatile oil (VO) was extracted from Rosmarinus officinalis, Lavandula angustifolia and Citrus aurantium by simultaneous hydro- and steam-distillation, and encapsulated in β-cyclodextrin by co-precipitation. Response surface methodology (RSM) was used to optimize microencapsulation conditions. The variable recovered powder, VO retention degree, and inclusion efficiency were investigated based on two factors: solid-to-liquid and liquid-to-liquid (ethanol/water) ratios. The responses were influenced by the concentration of ethanol in the reaction mixture and the amount of VO used. VO release from the inclusion complexes was investigated in 10% ethanol and in 3% acetic acid. The obtained data were fitted to the first-order Korsmeyer-Peppas, Higuchi, and Peppas-Sahlin models. The Higuchi model gave the fittest approach for the VO release profile in both cases, showing that the release mechanism was controlled by Fickian diffusion.
Dimensionality, bias, independence and measurement scale problems in latent trait test score models

It is argued that latent trait models used in the analysis of test scores, in particular the Rasch model, suffer from serious defects. They assume implicitly a measurement scale model for which little substantive justification seems to be available and they make the assumption of ‘local independence’ which enjoys little empirical support. Perhaps their most serious drawback, which is illustrated with the fixed effects' Rasch model, is that the individual ability estimates obtained are always biased. This bias is not constant but depends upon an individual's true ability, the number of items in the test and their difficulty values. Moreover, there is no way to obtain an unbiased estimate in the typical case when only one administration of a test is given to individuals. This result suggests that the use of such models needs to be critically examined, especially in connection with so-called ‘item banks’. The paper also discusses the dimensionality of the latent space, and shows how multidimensional models may be specified.
A role of singletons in quantum central limit theorems

A role of singletons in quantum central limit theorems is studied. A common feature of quantum central limit distribu· tions, the singleton condition which guarantees the symmetry of the limit distributions, is revisited in the category of discrete groups and monoids. Introducing a general notion of quantum independence, the singleton independence which include the singleton condition as an extremal case, we clarify the role of singletons and investigate the mechanism of arising non-symmetric limit distributions.
The metallicity-redshift relations for emission-line SDSS galaxies: examination of the dependence on the star formation rate

We analyse the oxygen abundance and specific star formation rates (sSFR) variations with redshift in star-forming SDSS galaxies of different masses. We find that the maximum value of the sSFR, sSFRmax, decreases when the stellar mass, Ms, of a galaxy increases, and decreases with decreasing of redshift. The sSFRmax can exceed the time-averaged sSFR by about an order of magnitude for massive galaxies. The metallicity - redshift relations for subsamples of galaxies with sSFR = sSFRmax and with sSFR = 0.1sSFRmax coincide for massive (log(Ms/Mo) > 10.5, with stellar mass Ms in solar units) galaxies and differ for low-mass galaxies. This suggests that there is no correlation between oxygen abundance and sSFR in massive galaxies and that the oxygen abundance correlates with the sSFR in low-mass galaxies. We find evidence in favour of that the irregular galaxies show, on average, higher sSFR and lower oxygen abundances than the spiral galaxies of similar masses and that the mass - metallicity relation for spiral galaxies differs slightly from that for irregular galaxies. The fact that our sample of low-mass galaxies is the mixture of spiral and irregular galaxies can be responsible for the dependence of the metallicity - redshift relation on the sSFR observed for the low-mass SDSS galaxies. The mass - metallicity and luminosity - metallicity relations obtained for irregular SDSS galaxies agree with corresponding relations for nearby irregular galaxies with direct abundance determinations. We find that the aperture effect does not make a significant contribution to the redshift variation of oxygen abundances in SDSS galaxies.
High piezoelectric properties of cement piezoelectric composites containing kaolin

To obtain high piezoelectric properties, PZT/cement composites with kaolin were fabricated and polarized by 1.5kV/mm electric field for 40 min, where lead zirconate titanate (PZT) inclusion with 50% by volume was used. After the polarization, piezoelectric properties of the composite were measured daily till 100 days. Results indicated that relative dielectric constant (εr) and piezoelectric strain constant (d33) increase with aging day, and approach to asymptotic values after 70 days. Temperature treatment to the composite is a dominate factor to enhance piezoelectric properties. The d33 and εr values of PZT/cement composites treated at the ambient temperature (23℃) were 57pC/N and 275 at the 70th aging day respectively, and then reached 106pC/N and 455 in turn with 150℃ treatment. The composite contains 4% kaolin having the highest value of d33=111pC/N and εr=500 at 90 days because the porosity is the less than the others. Cement piezoelectric composites containing kaolin own the higher d33 and εr value, compared with the other reported composites with 50% PZT. The porosity, the electromechanical coupling factor and impedance-frequency spectra of the cement piezoelectric composites were also discussed.
Corrugated Subwavelength Aperture Antenna with a Superstrate Layer

Abstract In this study, a subwavelength aperture antenna with multiple corrugations and a superstrate layer was investigated based on Fourier transform and mode matching, demonstrating a rigorous and fast convergent series solution. The aperture antenna with a corrugated conducting flange and a dielectric superstrate was fabricated in the X-band frequency range to demonstrate the validity of the derived series solution. The measured reflection coefficient and radiation pattern of the proposed antenna are also presented and compared to the computational results to assess the effect of the dielectric superstrate. A maximum gain enhancement of 5.19 dB was achieved by employing the superstrate.