Miracle-dz/UniFAR-FTUs huggingface dataset:
Scattering of VHF and UHF radar signals from the turbulent air

In the derivation of Booker-Gordon scattering cross sections in a turbulent atmosphere, certain assumptions have been made so that the power scattered within the scattering volume will add coherently. This results in a scattered power that is proportional to the effective scattering volume. As the scattering volume increases without bound, it leads to a physically unreasonable result of infinite scattered power. In this paper we examine these assumptions. In particular, we study the scattering cross sections, taking into account the possible phase incoherence of the scattered fields within the scattering volume. In addition, the effect of a thin turbulent layer on the complex autocorrelation function is investigated. The turbulence is assumed to be locally frozen. Expressions for both the Doppler shift and the correlation time have been derived.
Elastic effects of an insoluble surfactant on the onset of two-dimensional Faraday waves: a numerical experiment

The elastic effects of an insoluble surfactant on the formation and evolution of two-dimensional Faraday waves is investigated numerically. We analyse the influence of the elasticity of the surface-active agent on the amplitude of the vertical vibration needed to excite two-dimensional standing waves on the free surface. The numerical solutions show that the interface is always subharmonically excited at the onset and that the presence of the surfactant requires a higher external force to induce standing waves. They also show that the magnitude of the external amplitude is related to the temporal phase shift that exists between the evolution of the surfactant concentration and the free-surface shape. A detailed description of the time-varying velocity fields and interfacial distribution of surfactants helps to provide insight into the mechanisms ruling the phenomenon.
Magneto-Volume Effect in the Weak Itinerant Ferromagnet MnSi

The magneto-volume effect of the weak itinerant ferromagnet MnSi has been studied by measuring both the thermal expansion over a wide range of temperature and the forced volume megnetostriction at different temperatures. The forced magnetostriction at 4.2 K as well as the magnetic thermal expansion at 10 kOe, Δω m ( H , T ) can well be described by a formula Δω m ( H , T )= K C Δ[ M ST ( H , T ) 2 ] with K C =1.5×10 -10 (mol/emu) 2 where Δ[ M ST ( H , T ) 2 ] is the change of square of magnetization by polarization of the d band. The spontaneous magnetostriction at 0 K, Δω m (0,0) is related to the spontaneous magnetization M (0,0) by \(\Delta\omega_{\text{m}}(0,0){\doteqdot}(2/5)KC\ M(0,0)^{2}\) with the same K C . Furthermore magneto-v olume effect becomes positive above T c . All of these features agree satisfactorily with those predicted by Moriya and Usami based on spin fluctuation theory.
Fast ambipolar carrier transport in smectic phases of phenylnaphthalene liquid crystal

The carrier transport of a new calamitic liquid crystal, i.e., 2-(4′-octylphenyl)6-dodecyloxynaphthalene (8-PNP-O12) was investigated by the time-of-flight technique. The fast ambipolar electronic conduction was observed in two smectic phases of 8-PNP-O12. The carrier mobilities were determined to be 1.6×10−3 cm2/V⋅s in the lower temperature smectic phase (Sm1) between 79 and 100 °C and to be 2.5×10−4 cm2/V⋅s in the higher temperature phase (Sm2) between 100 and 121 °C, regardless of carrier signs, i.e., electron and hole. The slower ambipolar transport was observed in isotropic phase as well, whose mobility was 8×10−5 cm2/V⋅s. These mobilities were independent of applied electric fields and temperature.
Particle acceleration in collisionless shocks: regulated injection and high efficiency.

It is shown that under very general assumptions collisionless shocks can produce cosmic rays out ot an initially cold plasma with an efficiency of order unity. Heavy elements are preferentially accelerated relative to protons, as is observed. The nonthermal character of a wide variety of astrophysical systems can be accounted for by invoking collisionless shocks.
The Evolutionary Status of Isolated Dwarf Irregular Galaxies. I. UBV and Hα Imaging Observations

The results of UBV and Hα imaging of a large sample of gas-rich, isolated, dwarf irregular galaxies are presented. The majority of the low-luminosity systems in this sample have no known neighbors within 200–400 kpc and thus are unlikely to have had significant interactions within the last several gigayears. The new observations confirm that dwarf irregular galaxies are blue systems, with median values for the sample of 0.42± in B-V and -0.22± in U-B. Analysis of the derived surface photometry indicates that most of these systems can be well fitted by single exponential disks and have only minor color gradients. Furthermore, the observed H II regions are distributed sparsely across the optical disk. H II region luminosity functions were constructed for those systems with a sufficient number of H II regions; the derived power-law indices are generally shallow, with a median value of -1.61±.
Title of communication: A vertical fountain dryer adjusted to sawdust and chips drying, 22nd International Drying Symposium (IDS 2022)

This article presents preliminary results of research work on the drying process in a fountain dryer designed and adapted to drying sawdust and/or chips of various morphology. The phenomena occurring during the drying of sawdust in a fountain dryer were analyzed. Modifications of a typical fountain dryer were proposed in order to dry the chips, to get appropriate moisture and quality suitable for the process of their further granulation for the production of pellets. The test stand and the most important properties of the fountain dryer were described and discussed. Such characteristics of the device as i.e. efficiency, combustion, air and exhaust gas flow measurements, among others were presented. The characteristics of the sawdust drying curves as a function of temperature were also determined. Computer simulations of heat exchange, air, and exhaust gas flow velocities were also performed and compared with the results obtained directly from the modified test stand.
Computational homogenization of elasticity on a staggered grid

In this article, we propose to discretize the problem of linear elastic homogenization by finite differences on a staggered grid and introduce fast and robust solvers. Our method shares some properties with the FFT‐based homogenization technique of Moulinec and Suquet, which has received widespread attention recently because of its robustness and computational speed. These similarities include the use of FFT and the resulting performing solvers. The staggered grid discretization, however, offers three crucial improvements. Firstly, solutions obtained by our method are completely devoid of the spurious oscillations characterizing solutions obtained by Moulinec–Suquet's discretization. Secondly, the iteration numbers of our solvers are bounded independently of the grid size and the contrast. In particular, our solvers converge for three‐dimensional porous structures, which cannot be handled by Moulinec–Suquet's method. Thirdly, the finite difference discretization allows for algorithmic variants with lower memory consumption. More precisely, it is possible to reduce the memory consumption of the Moulinec–Suquet algorithms by 50%. We underline the effectiveness and the applicability of our methods by several numerical experiments of industrial scale. Copyright © 2015 John Wiley & Sons, Ltd.
Formation and evolution of early-type galaxies – III. Dependence of the star formation history on the total mass and initial overdensity

We investigate the influence of the initial overdensities and masses of proto-galaxies on their subsequent evolution (the star formation history in particular) to understand whether these key parameters are sufficient to account for the varied properties of the galactic populations. By means of fully hydrodynamical N-body simulations performed with the code EvoL, we produce 12 self-similar models of early-type galaxies of different initial masses and overdensities, and follow their evolution from the early epochs (detachment from the linear regime and Hubble flow at z ≥ 20) down to the stage when mass assembly is complete, i.e. z ≤ 1 (in some cases the models are calculated up to z = 0). The simulations include radiative cooling, star formation, stellar energy feedback, re-ionizing photo-heating background and chemical enrichment of the interstellar medium; we do not consider the possible presence of active nuclei. We find a strong correlation between the initial properties of the proto-haloes and their subsequent star formation histories. Massive (Mtot ≃ 1013 M⊙) haloes experience a single, intense burst of star formation (with rates ≥103 M⊙ yr−1) at early epochs, consistently with observations, with less pronounced dependence on the initial overdensity; intermediate-mass (Mtot ≃ 1011 M⊙) haloes have histories that strongly depend on their initial overdensity, whereas low-mass haloes (Mtot ≃ 109 M⊙) always have erratic, bursting like star-forming histories, due to the ‘galactic breathing’ phenomenon. The model galaxies have morphological, structural and chemical properties resembling those of real galaxies, even though some disagreement still occurs, likely a consequence of some numerical choices. We conclude that total mass and initial overdensity drive the star formation histories of early-type galaxies. The model galaxies belong to the so-called quasi-monolithic (or early hierarchical) scenario in the sense that the aggregation of lumps of dark and baryonic matter is completed very early on in their history. In this picture, nature seems to play the dominant role, whereas nurture has a secondary importance.
Deep level defects in electron-irradiated 4H SiC epitaxial layers

Deep level defects in electron-irradiated 4H SiC epitaxial layers grown by chemical vapor deposition were studied using deep level transient spectroscopy. The measurements performed on electron-irradiated p+n junctions in the temperature range 100–750 K revealed several electron traps and one hole trap with thermal ionization energies ranging from 0.35 to 1.65 eV. Most of these defects were already observed at a dose of irradiation as low as ≈5×1013 cm-2. Dose dependence and annealing behavior of the defects were investigated. For two of these electron traps, the electron capture cross section was measured. From the temperature dependence studies, the capture cross section of these two defects are shown to be temperature independent. © 1997 American Institute of Physics.
Novel 1×N and N×N integrated optical switches using self‐imaging multimode GaAs/AlGaAs waveguides

We report the demonstration of novel multiway GaAs/AlGaAs electro‐optic waveguide switches which incorporate self‐imaging planar multimode waveguide splitters and recombiners interconnected by single‐mode guides. Each device consists of one or more input guides, a multiway splitter, an array of individually addressed electro‐optic waveguide phase shifters, a multiway recombiner, and an array of output guides. By controlling the voltage applied to the electro‐optic guides, light from any one input guide can be switched to any one output guide. We present experimental results for 1×10 and 10×10 devices. Typical values for switching uniformity, maximum crosstalk, and insertion loss were ±9%, −10 dB, and −12 dB, respectively.
Kinematic constraints on models of the BL Lacertea object OJ 287 from VLBI polarization observations

Recently published VLBI polarization observations of OJ 287 are discussed in terms of simple theoretical models. It is shown how kinematic constraints can be derived directly from the polarization data. For a simple ballistic model, in which the pattern and emitting material have the same velocity, the high degree of polarization combined with the comparatively small apparent speed constrain the Doppler shift to be less than 4.6, a smaller value than that required by X-ray and variability data. A model based on shocks in a purely relativistic jet is consistent with the available data and permits Doppler shifts as large as 7.5. In this model the shocks are propagating more slowly than the fluid. 22 references.
Some results on generalized difference estimation and generalized regression estimation for finite populations

Let S = {s} be the set of subsets of {1, . , N} such that each s eS contains n elements. We consider in this paper only designs p(s) with fixed sample size, that is P(S) > 0 only if s eS and ESp(s) = 1, where Es denotes summation over s eS. Let p(s) be independent of the Yk, where Yk is the value of the variable of interest for the population unit labelled k (k = 1, ., N). We consider a superpopulation model: Yl, . , YN is a realization of Y1, . ,YN with joint distribution 6. If d(. ) denotes expectationwith respect to 6, let, for k, I = 1, . , N, 6 be further specified by
Using a Stochastic Kinetic Energy Backscatter Scheme to Improve MOGREPS Probabilistic Forecast Skill

AbstractAn improved stochastic kinetic energy backscatter scheme, version 2 (SKEB2) has been developed for the Met Office Global and Regional Ensemble Prediction System (MOGREPS). Wind increments at each model time step are derived from a streamfunction forcing pattern that is modulated by a locally diagnosed field of likely energy loss due to numerical smoothing and unrepresented convective sources of kinetic energy near the grid scale. The scheme has a positive impact on the root-mean-square error of the ensemble mean and spread of the ensemble. An improved growth rate of spread results in a better match with ensemble-mean forecast error at all forecast lead times, with a corresponding improvement in probabilistic forecast skill from a more realistic representation of model error. Other examples of positive impact include improved forecast blocking frequency and reduced forecast jumpiness. The paper describes the formulation of the SKEB2 and its assessment in various experiments.
A Characteristic Magnetic Field Pattern Associated with All Major Solar Flares and Its Use in Flare Forecasting

Solar flares result from some electromagnetic instability that occurs within regions of relatively strong magnetic field in the Sun's atmosphere. The processes that enable and trigger these flares remain topics of intense study and debate. I analyze observations of 289 X- and M-class flares and over 2500 active region magnetograms to discover (1) that large flares, without exception, are associated with pronounced high-gradient polarity-separation lines, while (2) the free energy that emerges with these fibrils is converted into flare energy in a broad spectrum of flare magnitudes that may well be selected at random from a power-law distribution up to a maximum value. This maximum is proportional to the total unsigned flux R within ~15 Mm of strong-field, high-gradient polarity-separation lines, which are a characteristic appearance of magnetic fibrils carrying electrical currents as they emerge through the photosphere. Measurement of R is readily automated, and R can therefore be used effectively for flare forecasting. The probability for major flares to occur within 24 hr of the measurement of R approaches unity for active regions with the highest values of R around 2 × 1021 Mx. For regions with R ≲ 1019 Mx, no M- or X-class flares occur within a day.
Instability in Parallel Flows Revisited

An example of an unstable inviscid plane parallel shear flow with classical boundary conditions is presented. The complete unstable spectrum is exhibited using techniques of continued fractions for the shear flow with profile U(y)=cos m y. For such flows spectral instability implies nonlinear instability. A three‐dimensional generalization is discussed.
Role of E-trust, E-loyalty, and E-satisfaction on Online Buying Behaviour among Millennials in Kuala Lumpur, Malaysia

The number of internet users in Malaysia is growing, and millennials are becoming the strongest in buying power. This research aimed was to investigate the influence of e-trust, e-loyalty, and e-satisfaction on online buying behaviour among millennials. Despite the growth of e-commerce and the high engagement of millennials in technology, there is a shortage of empirical research covering the determinants of online buying behaviour among millennials in Malaysia. This quantitative study collected primary data through a self-completed questionnaire that was sent through a survey method to millennials online shoppers in Malaysia. The target population was millennials engaged in online shopping. The research results revealed that e-loyalty and e-satisfaction are determinants of online buying behaviour among millennials. Surprisingly, this study found that e-trust was not a significant determinant of online buying behaviour. There are several practical implications of this study on marketeers and web‐retailers. This research will provide a better understanding to enable the web-retailers and marketers to develop their strategies to improve the online shopping experience of millennials. This is the first study that examined the relationship between e-trust, e-loyalty, and e-satisfaction with millennials' online shopping behaviour in the Malaysian context.
A Parsimonious Description of the Hendry System

In this paper we will present some basic concepts of the Hendry System and derive the results claimed in the HendroDynamics Chapters [HendroDynamics: Fundamental Laws of Consumer Dynamics, Hendry Corporation, Chapter 1 (1970) and Chapter 2 (1971). ] from two simple probabilistic assumptions; namely, zero order consumers and switching proportional to market share. We will develop the notion of partitioning which constitutes a major component of the Hendry System by briefly describing the procedure for identifying the partitioning structure in a given market. With this illustration we will point out various implications which can be drawn from a correctly identified market structure. All of our results are obtained without resorting to the entropy concept that has caused so much confusion in recent debates over the validity or usefulness of the Hendry Model.
Canonical partial least squares—a unified PLS approach to classification and regression problems

We propose a new data compression method for estimating optimal latent variables in multi‐variate classification and regression problems where more than one response variable is available. The latent variables are found according to a common innovative principle combining PLS methodology and canonical correlation analysis (CCA). The suggested method is able to extract predictive information for the latent variables more effectively than ordinary PLS approaches. Only simple modifications of existing PLS and PPLS algorithms are required to adopt the proposed method. Copyright © 2009 John Wiley & Sons, Ltd.
Internal, External, and Generalized Symmetries

Backlund′s theorem, which characterizes contact transformations, is generalized to give an analogous characterization of "internal symmetries" of systems of differential equations. For a wide class of systems of differential equations, we prove that every internal symmetry comes from a first order generalized symmetry and, conversely, every first order generalized symmetry satisfying certain explicit contact conditions determines an internal symmetry. We analyze the contact conditions in detail, deducing powerful necessary conditions for a system of differential equations that admit "genuine" internal symmetries, i.e., ones which do not come from classical "external" symmetries. Applications include a direct proof that both the internal symmetry group and the first order generalized symmetries of a remarkable differential equation due to Hilbert and Cartan are the noncompact real form of the exceptional simple Lie group G2.
Quasi-two-dimensional properties of a single shallow-water vortex with high initial Reynolds numbers

The evolution and dynamics of a shallow-water vortex system with high initial Reynolds numbers are investigated experimentally without background rotation. A single vortex is generated by rotating a water mass at the centre of an experimental tank using a bottomless cylinder with internal sectors. The surface velocity field is observed via particle image velocimetry. The experimentally observed vorticity fields indicate that strong shallowness (the ratio of the cylinder diameter to the water depth) and high Reynolds number contribute to the formation of large-scale coherent structures in the form of a tripolar vortex system. The shallow-water vortices with high initial Reynolds numbers experience the transition from turbulent to laminar regimes in their decay process. The proposed first-order vortex decay model predicts that a shallow-water vortex decays as t−1 in the initial turbulent stage and as e−t in the later laminar stage due to horizontal diffusion and bottom friction. The estimated transition time scale from the turbulent to laminar stage increases with initial vortex Reynolds number and with shallowness. By taking the vortex expansion into consideration, the second-order vortex decay model is also presented. The azimuthally ensemble-averaged data elucidate effects of the vortex instabilities and of turbulent energy transfer on the formation of large-scale coherent flow structures. Normal mode analysis of the vortex systems is conducted to study the effect of shallowness and Reynolds number on the generation of two-dimensional large-scale coherent structures. The results show that the perturbation wavenumber of mode 2 is the fastest-growing instability in shallow-water conditions, and its effect depends on initial Reynolds number and shallowness.
Interferometric measurement of the elongation of a pulsed diode laser

An interferometric technique was developed for detecting fast displacements of small areas in beam direction by less than \lambda/8 . It utilizes a modified Michelson interferometer and a He-Ne laser light source. The technique was applied to measure the temporal and spatial evolution of the thermal mirror deformation of a GaAs-Ga 1-x Al x As single heterostructure laser diode. A small spot on the facet of the laser diode formed one mirror of the interferometer. The other mirror was moved linearly with time by applying a ramp voltage to a piezoelectric transducer. The diode was pulsed during this motion. The local elongation of the laser diode was evaluated from the interferometer output signal. The measured elongation of the active region at a time 1 μs after a 150-ns pulse with current density 48 000 A/cm2was between 4 and 20 nm, indicating a temperature rise of 2-11\deg C. The smallest elongations detected were in the range of 0.5-1 nm. The measured values are in substantial agreement with theoretical expectations from thermal model calculations.
SURFACE WAVES IN A HEAT-CONDUCTING ELASTIC BODY: CORRECTION AND EXTENSION OF A PAPER OF CHADWICK AND WINDLE

In 1964 Chadwick and Windle published a detailed investigation of the secular equation governing the propagation of surface waves in a semi-infinite,isotropic, heat-conducting elastic body the surface of which is traction-free and either at constant uniform temperature or thermally insulated. The purpose of the present paper is first to remedy a defect in the work of Chadwick and Windle and then to extend the scope of their analysis by allowing the transmitting body to exchange heat with a constant-temperature environment. The defect arises from the insufficiency of the criteria used to decide whether or not a branch of the algebraic function defined by the rationalized secular equation represents a surface wave. When it is corrected the non-uniqueness of the surface-wave solutions found by Chadwick and Windle is removed and there exists precisely one quasi-elastic surface wave for all frequencies and for all values of the heat-transfer coefficient appearing in the thermal boundary condition, including th.