Miracle-dz/UniFAR-FTUs huggingface dataset:
High-Cycle Thermal Fatigue in Mixing Tees: New Large-Eddy Simulations Validated Against New Data Obtained by PIV in the Vattenfall Experiment

New data was obtained for a previously studied T-junction experimental setup [1] for a range of flow ratios between hot and cold flows in order to validate new Large Eddy Simulations (LES). The instantaneous velocity field downstream of the T-junction was measured with two-component Particle Image Velocimetry (PIV) in several horizontal and vertical planes at the centre line downstream of the T-junction. The generated PIV database enables a thorough validation of CFD turbulence statistics. The turbulence statistics are shown to be well predicted despite the fact that the mesh in the LES is rather coarse. By usage of time resolved PIV the temporal evolution of the predominant low frequent large-scale structures, responsible for much of the mixing and the high amplitude temperature fluctuations on the walls, were captured. Those structures are, however, weaker in LES than in PIV, being in line with the fact that the wake region behind the penetrating vertical hot jet is underpredicted in LES. Tests regarding the influence of the LES-results to the shape of the inlet boundary conditions (developed or flat symmetric mean-velocity profiles) were carried out and the sensitivity in the results was shown to be small. Furthermore, the results show good agreement with the experimental data independent of the flow ratio between the hot and the cold flows.Copyright © 2009 by ASME
Social support and associated factors among family caregivers of older people in North-East Peninsular Malaysia

Background The negative health results associated with the family caregivers of older people can be alleviated with social support, which is considered a valuable resource. Hence, the factors contributing to social support need to be understood. Objective This study aimed to evaluate the social support associated with the family caregivers of older people. Methods A cross-sectional study was conducted among 231 family caregivers of older people conveniently selected from two districts in Kelantan, a state in the North-East Region of Peninsular Malaysia. Data were gathered between June to December 2021 using a Multidimensional Scale of Perceived Social Support (MSPSS) questionnaire. Descriptive statistics were used to summarize the data in frequencies and percentages. Independent t-test and one-way analysis of variance were used to examine correlations among variables. Results The mean scores of social support for family caregivers were significantly higher among their family (Mean ± SD; 5.44 ± 0.969) and other important people (5.25 ± 1.123) compared to their friends (4.84 ± 1.094). Caregivers’ gender and duration of caregiving were significant factors associated with social support (p <0.05). Conclusions The family caregivers received maximum support from their family and other important people, but they were less supported by their friends. This study also observed that the perceived social support of the caregivers of older people was affected by several factors, such as gender and duration of caregiving. This finding gives nurses and other healthcare workers the basic information they need to enhance nursing interventions and promote social support among those who care for older people, which can positively impact caregiving.
Self-similar solutions for elastohydrodynamic cavity flow

The enlargement of a lens-shaped cavity lying in a plane of cleavage between two elastic half spaces and filling with viscous fluid from a source on the axis of symmetry is considered. The internal flow is modelled by lubrication theory, which gives a nonlinear partial differential equation connecting the pressure to the cavity shape, and the same two quantities are also related by the singular integral equation of linear elasticity. If the total volume of fluid Q(t) in the cavity at time t is proportional either to tα or to exp (αt) the resulting boundary value problem can be reduced to a self-similar form in which time does not appear explicitly. The solution in non-dimensional terms depends on a single parameter, which may be interpreted as the stress-intensity factor K at the tip. Calculations have been made for the two-dimensional version of the problem for a range of values of α and for a range of stress intensities. The numerical method is to expand the cavity height in a Chebyshev series, the coefficients being found by a nonlinear optimization technique to yield a least squares fit to the Reynolds equation. These lead to expressions for the rate of cavity growth and other quantities of physical interest.
Perception or Confidence? Self-Concept, Self-Efficacy and Achievement in Mathematics: A Longitudinal Study

The Third International Mathematics and Science Study research of the International Association for the Evaluation of Educational Achievement reported in 2003 that Taiwanese fourth- and eighth-graders' mathematics performance exceeded the international average; both groups ranked fourth from among all the participant countries. However, the Index of Students' Self-Confidence in Learning Mathematics was below the international average for both these groups. This study, coming at the end of the first year of a three-year project, explored Taiwanese students' mathematics learning at the high school level from a social cognitive perspective. Utilising structural equation modelling, it examined the relationships among mathematics self-concept, mathematics self-efficacy and mathematics achievement using a longitudinal design. The subjects included 2198 seventh- and tenth-graders from Taiwan. The results indicate a significant correlation between mathematics self-concept and mathematics self-efficacy as well as significant longitudinal effects. Mathematics achievement at Time 1 significantly predicted the mathematics self-concept, mathematics self-efficacy and mathematics achievement at Time 2, while mathematics self-concept and mathematics self-efficacy at Time 1 significantly predicted mathematics achievement at Time 2. The implications of these findings are discussed from the viewpoint of cultivating the students' interest and confidence in learning mathematics, and suggestions are provided for further research.
Image‐based Continuous Displacement Measurements Using an Improved Spectral Approach

Digital Image Correlation algorithms capable of determining continuous displacement fields are receiving growing attention in the field of mechanical properties identification. In this paper, we develop an Improved Spectral Approach (ISA) to reconstruct continuous displacements based on their Fourier decomposition. This approach leads to a time and memory‐efficient algorithm, thanks to the fast Fourier transform. Moreover, the Fourier‐based decomposition enables accurate heterogeneous measurements. Improvements consist in increasing the accuracy and convergence rate as well as dealing with non‐periodic displacements and images. Furthermore, a theoretical framework is presented to quantify the noise sensitivity of the ISA from which useful information is retrieved. The approach is evaluated using synthetic images deformed by heterogeneous displacement fields. Comparisons show that the introduced modifications lead to lower uncertainties by one order of magnitude in the case of non‐periodic images and displacement field studied. Moreover, first‐order (SO1) and second‐order (SO2) subset‐based Digital Image Correlation algorithms are compared with the ISA. The comparisons herein reveal that the uncertainties of the ISA are 6–9 times smaller than those of the SO1 due to insufficiency of the first‐order shape function for the estimation of heterogeneous displacements, while being slightly smaller than those of the SO2. Moreover, as the image smoothness decreases, the uncertainties of the SO2 deviate from those of the ISA and the exact displacements. The presented approach shows great potentials for challenging applications such as strain measurements at microstructural levels.
Design and Deployment of a Portable, Pencil-Beam, Pulsed, 3-cm Doppler Radar

Abstract A portable, pencil-beam, pulsed, Doppler, 3-cm wavelength radar has been constructed to study a wide variety of meteorological phenomena including tornadoes, severe storms, and boundary layer processes. The new radar, the Doppler on Wheels (DOW), has full scanning capability, a real-time display and archiving, and is mounted on a truck for easy portability and full mobility. This portability allows the radar to be brought to within a kilometer of rare meteorological phenomena. At this range, the pencil beam of the radar is very narrow, permitting significantly higher-resolution measurements (at 3-km range, 64 m × 64 m × 75 m) than are usually possible with stationary or airborne systems. The radar employs a new high-powered, PC-based, digital intermediate frequency (IF) data acquisition scheme called the PIRAQ. The radar has successfully collected data in several tornadoes and tornadic storms and has been used to detect dust devils and other boundary layer structures. The sensitivity and mobility.
Study of optical properties and effective three-photon absorption in Bi-doped ZnO nanoparticles

In this paper we report the linear and nonlinear optical properties of Bi-doped ZnO nanoparticles. Bi-doped ZnO nanoparticles were prepared through the wet chemical method at room temperature. Optical absorption measurements show that the exciton peaks are situated at 272 and 368 nm, which are attributed to the n=2 and n=1 exciton states, respectively. Transmission electron microscopy measurements reveal the size and shape of the particles and energy dispersive X-ray measurements confirm the doping of Bi in ZnO. Steady state photoluminescence measurements show that the emission is composed of five peaks. Open aperture z-scan measurements done at 532 nm using 5 ns, 300 μJ laser pulses reveal nonlinear absorption which arises from an effective three-photon absorption process.
Elimination of spurious solutions from eight-band k.p theory

A method is developed for eliminating spurious solutions from eight-band $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ theory. It reduces the bulk dispersion to a cubic equation (quadratic along $〈001〉$ and $〈111〉)$, yet gives results virtually indistinguishable from ordinary $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ theory. A unique operator ordering is established for heterostructures, and example calculations on superlattices show good results.
Solar cycle and quasi-biennial variations in helioseismic frequencies

Abstract The prolonged period of solar minimum between cycles 23 and 24 has invoked a great deal of interest to understand the origin of the unusually low solar activity. Even though the origin of solar activity is believed to lie in the shear layer at the base of the convection zone, the analysis of helioseismic data seem to orientate us toward the near surface. In this context, we analyze the signature of the quasi-biennial periodicity seen in the oscillation frequencies which may provide additional constraints on the solar dynamo models.
The role of representations in students’ intuitive thinking about infinity

Initial investigations suggest that students’ intuitive decisions concerning the equivalency of two given infinite sets are largely determined by the way these sets are represented. So far the effects of two types of representations were investigated: the numerical‐horizontal and the numerical‐vertical representations. Our study was mainly aimed at determining which representations (numerical‐horizontal, numerical‐vertical, numerical‐explicit or geometric) yielded higher percentages of one‐one correspondence reactions. For these purposes, 189 middle class 10th to 12th graders were asked to react to 14 problems dealing with comparing infinite sets. The problems presented different representations of the same infinite sets. It was found that one‐one correspondence justifications were mainly elicited by numerical‐explicit and by geometric representations. The discussion suggests ways of adjusting these findings to two different approaches to teaching: analogy and conflict.
On the Direction of the Eddy Momentum Flux in Baroclinic Instability

Abstract The direction of the vertically-integrated horizontal eddy flux of momentum in linear baroclinically unstable modes is investigated in a number of cases where the basic flow contains horizontal, as well as vertical, shear. A general result is presented for slowly-growing modes on a flow with weak horizontal shear. Some special cases are described in which standard baroclinic instabilities of finite growth rate (for an internal jet, Eady's model, and a two-layer model) are perturbed by weak horizontal shear, and some computations for flows with large horizontal shear are also mentioned. A general rule emerging from these calculations is that for flows with horizontal jet structure of broader scale than the radius of deformation, the vertically-integrated momentum flux tends to be into the jet (or upgradient); while for jets narrower than the radius of deformation, momentum fluxes tend to be out of the jet (downgradient), even when the contribution of horizontal curvature to the basic state potenti.
Modelling the effect of imperfect vaccines on disease epidemiology

We develop a mathematical model to monitor the effect of imperfect vaccines on the transmission dynamics of infectious diseases. It is assumed that the vaccine efficacy is not $100\%$ and may wane with time. The model will be analyzed using a new technique based on some results related to the Poincare index of a piecewise smooth Jordan curve defined as the boundary of a positively invariant region for the model. Using global analysis of the model, it is shown that reducing the basic reproductive number ($\mathcal{R}_0$) to values less than one no longer guarantees disease eradication. This analysis is extended to determine the threshold level of vaccination coverage that guarantees disease eradication.
Interplanetary magnetic field polarities inferred from the north–south cosmic ray anisotropy

[1] The interplanetary magnetic field sector polarity at the Earth's location can be inferred from ground measurements of the cosmic ray north-south anisotropy. We present here the results of a systematic comparison between inferred and directly measured polarities in the period from January 1971 through December 1997. The overall success rate of the prediction method is 72%, in rather good agreement with previous findings. On the other hand, our analysis shows for the first time the limits of the method and calls for warning in its use. In fact, it turns out that the inferred polarities are affected by a bias, which becomes more relevant around the sunspot minimum. Even though the bias cannot be removed, it is possible to select conditions, occurring for 30% of the time, under which the inferred polarities are very reliable (the success rate being 95%).
A survey with Copernicus of interstellar O VI absorption

The presence of broad, shallow absorptions caused by O VI ions were revealed from UV spectra observations recorded by the Copernicus satellite for thirty-two stars. A table lists survey data on the stars observed for which values of the O VI column densities or their upper limits are extracted. Interstellar rather than circumstellar origin is evident from observation of the lack of correspondence between radical velocities of the stars and those of the O VI profiles. The presence of a low-density high-temperature phase of interstellar gas produced by supernova explosions is suggested.
Convection related phenomena in granular dynamics simulations of vibrated beds

Three-dimensional discrete element simulations are carried out to investigate the behavior of a shallow bed of inelastic, frictional spheres (of uniform diameter d), which are energized by vertical sinusoidal oscillations of a plane floor at amplitude a and frequency ω=2πf. We investigate the long-term and instantaneous velocity fields as well as the evolution of the pressure tensor. Results show that the onset of convection reported in the literature is not only determined by the floor acceleration, but also the ratio a/d. In a wide bed (L/d∼100) narrow persistent vortices appear near vertical sidewalls, while no distinct pattern is found within the central region. A large sphere within the bed is convected upward to the surface and either “segregates” itself from the bulk, or becomes reentrained, depending on the width of the downward velocity field near the wall relative to the sphere size. An inspection of the bed microstructure reveals internal vortex-like cells spanning its width giving rise to arch.
Error Estimates for Passive Satellite Measurement of Surface Pressure Using Absorption in the A Band of Oxygen

Abstract This paper investigates the feasibility of satellite remote sensing of surface pressure using radiometric measurements in the oxygen A band. It is shown out the primary sources of error are the uncertainties in the temperature profile, the surface reflection coefficient, and the aerosol loading. The impact of each of these errors upon the surface pressure is estimated. Pressure measurements to better than 2 hPa accuracy appear possible in principle over a wide range of surface reflectances if the temperature profile is known to an accuracy of 1 K, if the aerosol loading is known to an accuracy of 10%, and if instrumental noise can be limited to 0.1%. However, the calculations of this paper suggest that the radiometer must sample over extremely narrow spectral windows (1 cm−1) if this accuracy is to be achieved.
Photonic band structures of one- and two-dimensional periodic systems with metallic components in the presence of dissipation

We present an approach that allows calculating photonic band structures of electromagnetic waves propagating in periodic systems containing dispersive and highly absorptive materials characterized by a dielectric function, which is frequency dependent and has a non-negligible imaginary part. This method, which provides a complementary approach to that of the transfer-matrix method, is based on the use of a position-dependent dielectric function and the plane-wave technique. The use of the complex form of the dielectric function transforms Maxwell’s equations into a generalized nonlinear eigenvalue problem. At low filling fractions of the dispersive and absorptive component ( f <1%), the generalized eigenvalue problem is reduced to a problem of solving sets of simultaneous nonlinear equations which correspond to the diagonal terms of the matrix equation in the plane-wave representation, with the nondiagonal elements taken into account perturbatively. The resulting complex band structure yields, in addition to the dispersion curves, the attenuation of each mode as it propagates through the system. We first consider a model system represented by a one-dimensional ~1D! periodic array of alternating layers of vacuum, and a metal characterized by the complex frequency-dependent dielectric function. To calculate the photonic band structure of this system we employ, in addition to the transfer-matrix method and our perturbative plane-wave approach, a standard linearization technique which solves the general nonlinear eigenvalue problem by the diagonalization of an equivalent, enlarged, matrix. We then apply both our perturbative plane-wave approach and the linearization scheme to obtain the photonic band structures of an infinite array of parallel, infinitely long metallic rods whose intersections with a perpendicular plane form a simple square lattice. The interesting features associated with the presence of dissipation displayed by the photonic band structures, such as an asymmetric behavior of the absorption coefficient and the lifetime of each electromagnetic wave for wave vectors near the Brillouin-zone boundaries, the splitting of the lifetimes of degenerate modes, and the different dependences of the real and imaginary parts of the complex photonic band structure on the polarization of the electromagnetic waves in 2D systems, are discussed. @S0163-1829~97! 07711-4#
Multifolded Polymer Solar Cells on Flexible Substrates

Arrays of reflective multijunction polymer solar cell were demonstrated by folding four separated cells fabricated on a single plastic substrate using conducting polymer poly(3, 4-ethylene-dioxythiophene):polystyrenesulfonate as an anode. The combination of flexible substrate and polymer solar cells (PSCs) makes the construction of multifolded PSCs on one substrate possible. The power conversion efficiency (PCE) of the multifolded reflective PSCs was enhanced by 62%±12% with the folded opening angle of 30° compared to the planar cells. In series connection of four solar cells, an open-circuit voltage (Voc) of 3.65V was obtained.
Special Families of Sets and Baer-Specker Groups

ABSTRACT We prove that the Baer-Specker group Π = contains a pure subgroup isomorphic to the direct sum of 2 0 copies of itself. We produce 2 ℵ 0 nonisomorphic subgroups of Π, each isomorphic to its dual group. Finally, we show that the isomorphism type of a generalized product of ℤ's, the set of functions I → ℤ with support of size at most α, uniquely determines both the cardinality of I and α (as long as there are no measurable cardinals ≤α). All three of these results are obtained using set-theoretic existence theorems, namely, the existence of large independent families, large almost disjoint families, and Δ-systems.
The chromospheric emission-age relation for stars of the lower main sequence and its implications for the star formation rate

An attempt is made to formulate the relationship between age and chromospheric emission (CE) in late-type dwarf stars. Evidence is reviewed that a deterministic relationship of this type actually exists, and that for stars of known age, either a power-law relation or a curve corresponding to a constant star formation rate fits equally well. Further observations should be able to demonstrate either that there is a real excess of young stars near the sun or that the evolution of CE for a low-mass star goes through a slow initial decline, a rapid decline at intermediate ages, and finally a slow decline for old stars like the sun. 100 refs.
A second‐order renormalization theory for cross‐polarized backscatter from a half space random medium

A second-order renormalization theory is formulated to calculate the cross-polarized backscattering cross sections from an isotropic half space random medium whose permittivity fluctuations are characterized by center-valued Gaussian statistics. The results show that the second-order theory predicts a significant level of depolarized backscatter, in contrast to the first-order theory, which has been shown to contain no depolarized backscatter except from anisotropy effects in the medium.