Miracle-dz/UniFAR-FTUs huggingface dataset:
On the periodic injection of fluid into, and its extraction from, a porous medium for seasonal heat storage

Abstract We examine the oscillatory motion of fluid which spreads under gravity along a horizontal impermeable boundary through a porous medium controlled by the periodic injection and extraction of fluid from a horizontal well. Over the first few cycles the volume of injected fluid exceeds that which is extracted owing to the gravitational spreading of the current. However, after many cycles, these volumes converge and the flow develops into two regions. Near the source there is a zone $0\lt x\lesssim {x}_{C} = 2. 4 \mathop{ (Q{\tau }^{2} S/ \phi )}\nolimits ^{1/ 3} $ in which the depth of the fluid varies periodically with each cycle, where $Q$ is the fluid injection rate, $\tau $ is the injection or extraction time, $S$ is the speed of the buoyancy-driven flow and $\phi $ is the porosity. The current attains its maximum depth, $1. 8 \mathop{ ({Q}^{2} \tau / {\phi }^{2} S)}\nolimits ^{1/ 3} $ at the source, where the minimum depth equals zero. At long times, the current depth at $x= {x}_{C} $ is approximately constant, $1. 15 \mathop{ ({Q}^{2} \tau / {\phi }^{2} S)}\nolimits ^{1/ 3} $ , and beyond this point, the current spreads horizontally, driven by an effective flux ${Q}_{l} \approx 0. 54Q \mathop{ (t/ \tau )}\nolimits ^{\ensuremath{-} 1/ 2} $ , so that the length of the current increases as ${x}_{\mathit{nose}} \approx 1. 73 \mathop{ (Q{\tau }^{2} S/ \phi )}\nolimits ^{1/ 3} \mathop{ (t/ \tau )}\nolimits ^{1/ 2} $ . We confirm these predictions with new experiments using a Hele-Shaw cell. We also model the evolution of the thermal front which develops if the injected fluid is hotter than the formation temperature. We find conditions under which all the extracted fluid is hot but owing to the mismatch between the volume of injected and extracted fluids, not all the injected thermal energy is recovered, and the surrounding rock heats up.
Fractal structures of zinc metal leaves grown by electrodeposition

Zinc metal leaves are grown two-dimensionally by electrodeposition. The structures clearly remind us of the random patterns simulated by computer according to the Witten-Sander diffusion-limited-aggregation model. The scale invariance is tested by computing the density-density correlation function for the digitized patterns of the photographs. The Hausdorff dimension averaged over many examples is $D=1.66\ifmmode\pm\else\textpm\fi{}0.03$, which is in excellent agreement with that of the two-dimensional diffusion-limited-aggregation model ($D\ensuremath{\cong}\frac{5}{3}$).
Phase contrast tomography: An alternative approach

Conventional microtomography is widely used for reconstructing the three-dimensional (3D) distribution of the absorption coefficient of a sample from a set of radiographic projections. The question here is whether the 3D distribution of the phase (refractive index) of a weakly absorbing object can be, alternatively to the combined phase retrieval-backprojection methods presented up to now, directly reconstructed from a single tomographic data set. In this letter a solution to this problem based on a direct filtered backprojection approach, derived from the transport of intensity equation, is investigated numerically and experimentally for monochromatic and polychromatic x rays. The results show that the contrast is increased, while keeping dose minimal and spatial resolution equivalent to the conventional absorption based technique. This method is therefore very promising for imaging of biological specimens.
Scattering theory of low-energy photon diffraction

To apply the layer iteration method of low-energy electron diffraction to the diffraction of UV and visible light, the transmission and reflection coefficients of the electromagnetic waves are derived for a two-dimensional periodic array of dielectric spheres with an isotropic dielectric constant. The concepts of phase shifts and t matrix are introduced for light scattering. The theory is a direct extension of Kambe's LEED theory (1968). Also, the secular equation obtained for the bandstructures of photons is a generalisation of the Korringa-Kohn-Rostoker formalism of electronic band calculation.
Design of a Fat-Based Adaptive Visual Servoing for Robots with Time Varying Uncertainties

Most present adaptive control strategies for visual servoing of robots have assumed that the unknown camera parameters, kinematics, and dynamics of visual servoing system should be linearly parameterized in the regressor matrix form. This is because the limitation of the traditional adaptive design in which the uncertainties should be time-invariant such that all time varying terms in the visual servoing system are collected inside the regressor matrix. However, derivation of the regressor matrix is tedious. In this article, a FAT (function approximation technique) based adaptive controller is designed for visual servo robots without the need for the regressor matrix. A Lyapunov-like analysis is used to justify the closed-loop stability and boundedness of internal signals. Moreover, the upper bounds of tracking errors in the transient state are also derived. Computer simulation results are presented to demonstrate the usefulness of the proposed scheme.
Machine-learning Modeling for Personalized Immunotherapy- An Evaluation Module

Immune-cell therapy and targeting therapy are in rapid development to treat tumor diseases. However, current immune-cell therapy and targeting immunotherapy often face three challenges (three Ss): safety challenges such as cytokine releasing syndrome (C.R.S.); specificity targeting problems such as low efficacy caused by off-targeting tumor cells; unsatisfying payment are confounded to clinical patients and physicians. We have been studying immunotherapy for more than thirty years, and recently, personalized immunotherapy to treat tumor disease has been proposed. After we discovered quiescent genes from immune cells within the tumor microenvironment, we set up single-cell genomics analysis, studying heterogeneous immune responses from multiple tumor antigens (neo-antigen); here, we further introduce a new generation of immunotherapy module by using a machine-learning model to assess optimal immunotherapy. The machine-learning model combined with single-cell genomic analysis can predict optimal immune-cell (such as T-cells) and other optimal targeting drugs such as PD1 and CTLA4 inhibitors for the patient to use.
ROOK THEORY. II: BOARDS OF BINOMIAL TYPE

We explore the relation between rook theory of Ferrers boards and polynomial sequences of binomial type. Recursion and explicit formulas for the rook numbers of Riordan’s trapezoidal boards are derived. It is shown that some classic sequences of rook and factorial polynomials are of binomial type. A class of boards corresponding to Abel’s theorem and its generalizations are constructed.The results are developed from both algebraic and combinatorial viewpoints.
Phase conjugation by degenerate four-wave mixing in absorbing media

A theory of degenerate four-wave mixing in absorbing media is developed in terms of a general nonlinear susceptibility. The predictions of the theory are examined in both high and low reflectivity regimes and the specific nonlinearity-inducing mechanisms of thermally induced refractive index changes, the Kerr effect, and saturable absorption are considered. Such a theory is of particular relevance to degenerate four-wave mixing experiments in the ultraviolet and the predictions of the theory are compared with results obtained from such experiments.
A new application of the Korteweg–de Vries Benjamin-Ono equation in interfacial electrohydrodynamics

We consider waves on a layer of finite depth governed by the Euler equations in the presence of gravity, surface tension, and vertical electric fields. We use perturbation theory to identify canonical scalings and to derive a Korteweg–de Vries Benjamin-Ono equation arising in interfacial electrohydrodynamics. When the Bond number is equal to 1∕3, dispersion disappears and the equation reduces to the Benjamin-Ono equation. In the additional limit of vanishing electric fields, we show how to obtain a new evolution equation that contains third- and fifth-order dispersion as well as a nonlocal electric field term.
Accurate Oscillator Strengths of Astrophysical Interest for Neutral Oxygen

Knowledge of accurate oscillator strengths in neutral oxygen is of crucial importance in astrophysics. The accurate determination of the solar abundance of O I, which remains the primary sources for the entry in cosmic abundance tables, requires the use of E1 transitions appearing in the solar photospheric spectrum. A new accurate scale of oscillator strengths has therefore been obtained for the 2p 3 ( 4 S)nl-2p 3 ( 4 S)n'l' transitions of O I of astrophysical interest. Configuration interaction effects have been considered in a detailed way. The results have been used to improve the solar abundance determination for oxygen.
Engagement with fact-checked posts on Reddit

Abstract Contested factual claims shared online are of increasing interest to scholars and the public. Characterizing temporal patterns of sharing and engagement with such information, as well as the effect of sharing associated fact-checks, can help us understand the online political news environment more fully. Here, we investigate differential engagement with fact-checked posts shared online via Reddit from 2016 to 2018. The data comprise ∼29,000 conversations, ∼849,000 users, and ∼9.8 million comments. We classified the veracity of the posts being discussed as true, mixed, or false using three fact-checking organizations. Regardless of veracity, fact-checked posts had larger and longer lasting conversations than claims that were not fact-checked. Among those that were fact-checked, posts rated as false were discussed less and for shorter periods of time than claims that were rated as true. We also observe that fact-checks of posts rated as false tend to happen more quickly than fact-checks of posts rated as true. Finally, we observe that thread deletion and removal are systematically related to the presence of a fact-check and the veracity of the fact-check, but when deletion and removal are combined the differences are minimal. Theoretical and practical implications of the findings are discussed.
The triple-peaked afterglow of GRB 210731A from X-ray to radio frequencies

GRB 210731A was a long-duration gamma-ray burst discovered by the Burst Alert Telescope (BAT) aboard the Neil Gehrels Swift observatory. Swift triggered the wide-field, robotic MeerLICHT optical telescope in Sutherland; it began observing the BAT error circle 286 seconds after the Swift trigger and discovered the optical afterglow of GRB 210731A in its first 60-second q-band exposure. Multi-colour observations of the afterglow with MeerLICHT revealed a light curve that showed three peaks of similar brightness within the first four hours. We present the results of our follow-up campaign and interpret our observations in the framework of the synchrotron forward shock model. We performed temporal and spectral fits to determine the spectral regime and external medium density profile, and performed detailed multi-wavelength theoretical modelling of the afterglow following the last optical peak at 0.2 days to determine the intrinsic blast wave parameters. We find a preference for a stellar wind density profile consistent with a massive star origin, while our theoretical modelling results in fairly typical shock microphysics parameters. Based on the energy released in gamma-rays and the kinetic energy in the blast wave, we determine a low radiative efficiency of ~0.02. The first peak in the optical light curve is likely the onset of the afterglow. We find that energy injection into the forward shock offers the simplest explanation for the subsequent light curve evolution, and that the blast wave kinetic energy increasing by a factor of ~1000 from the first peak to the last peak is indicative of substantial energy injection. Our highest-likelihood theoretical model overpredicts the 1.4 GHz flux by a factor of approximately three with respect to our upper limits, possibly implying a population of thermal electrons within the shocked region.
Maternal rumen and milk microbiota shapes the establishment of early-life rumen microbiota in grazing yak calves.

Early-life gut microbial colonization and development exert a profound impact on the health and metabolism of the host throughout the life span. The transmission of microbes from the mother to the offspring affects the succession and establishment of the early-life rumen microbiome in newborns, but the contributions of different maternal sites to the rumen microbial establishment remain unclear. In the present study, samples from different dam sites (namely, oral, rumen fluid, milk, and teat skin) and rumen fluid of yak calves were collected at 6 time points between d 7 and 180 postpartum to determine the contributions of the different maternal sites to the establishment of the bacterial and archaeal communities in the rumen during early life. Our analysis demonstrated that the dam's microbial communities clustered according to the sites, and the calves' rumen microbiota resembled that of the dam consistently regardless of fluctuations at d 7 and 14. The dam's rumen microbiota was the major source of the calves' rumen bacteria (7.9%) and archaea (49.7%) compared with the other sites, whereas the potential sources of the calf rumen microbiota from other sites varied according to the age. The contribution of dam's rumen bacteria increased with age from 0.36% at d 7 to 14.8% at d 180, whereas the contribution of the milk microbiota showed the opposite trend, with its contribution reduced from 2.7% at d 7 to 0.2% at d 180. Maternal oral archaea were the main sources of the calves' rumen archaea at d 14 (50.4%), but maternal rumen archaea became the main source gradually and reached 66.2% at d 180. These findings demonstrated the potential microbial transfer from the dam to the offspring that could influence the rumen microbiota colonization and establishment in yak calves raised under grazing regimens, providing the basis for future microbiota manipulation strategies during their early life.
First Mapping Observations of Two Possible Cloud Collision Candidates IRAS 02459+6029 and 05363+3127

The first mapping observations of the cold infrared sources IRAS 02459+6029 and 05363+3127 in the molecular lines 12CO(1–0), 13CO(1–0) and C18O(1–0) were made using the 13.7 m millimeter wave telescope in Qinghai. Both the integrated intensity maps and position-velocity diagrams show that each has two components adjacent in both space and velocity which means possible cloud-cloud collisions in the two regions. The near-infrared color-color diagram from the 2MASS database reveals that the density of YSOs in the colliding site is much higher than in the surrounding regions. The results appear to indicate that star forming activities have taken place in the two regions due to the cloud-cloud collision. We conclude that both sources are cloud collision candidates.
Switching modeling and bumpless transfer tracking control for the conversion mode of tilt-rotor aircraft

The modeling and state tracking control for the conversion mode of tilt-rotor aircraft are investigated with a switching modeling method and a bumpless transfer technique. Based on the Euler equation and the Blade element theory, the nonlinear model of conversion mode is deduced to illustrate the features of the tilting process. Afterward, the switching modeling method settles the linearization problem of the nonlinear control with an uncontrollable nacelle inclination signal. Meanwhile, it also transfers the conversion mode control issue to a reference state tracking control problem of switched linear systems. In addition, the H ∞ control is adopted to restrain the external disturbances, and the controller with bumpless transfer performance is designed to overcome the control jump at switching instants. Finally, an example of XV-15 tilt-rotor aircraft is proposed to illustrate the effectiveness of the developed method.
Contour-based object detection using generalized Hough transform

We present a novel contour-based object detector using generalized hough transform where each local part casts a vote for the possible locations of the object center. The angles of line segments as local feature are extracted to describe the contour of the object, then an improved voting tactics is applied to detect the location and attitude of the object. Experimental results demonstrate that the algorithm has an encouraging detection performance.
Distinct Conceptions of Freedom in East Asia and the Protestant West Underpin Unique Pathways of Societal Development

Western theories of modernization and cultural change suppose that socioeconomic development fosters support for freedom and equality in all societies. Cultural relativism and “Asian Values” thesis challenge such theories of universal human development by arguing that East Asian societies’ cultural legacies predispose them to a distinct pathway of cultural and societal development. This study uses nationally representative data from the World Values Survey and European Values Study to test whether East Asian and hystorically Protestant Western societies hold six domains of freedom aspirations as strongly as their level of socioeconomic development predicts. Protestant Western nations score consistently high on all freedom aspirations, while East Asia’s scores are higher than predicted for personal autonomy and secular identity but lower for the other four domains: individual freedom, gender equality, political liberalism, and ethnic tolerance. Multidimensional scaling reveals clearly distinguishable Protestant Western and East Asian cultural models. The dimensions these models are depicted by are associated with various salient societal outcomes. East Asia’s emphasis on personal autonomy and secular identity is compatible with good physical and mental health, low crime, competitive economy, and educational achievements. Protestant West’s support for other aspects of freedom is associated with high subjective well-being, demographic sustainability, human rights and rule of law, democratic institutions, and gender equality. Convergence in cultural and societal development may not be expected in the foreseeable future.
Gain scheduled control for discrete‐time systems depending on bounded rate parameters

In this paper we consider a linear, discrete‐time system depending multi‐affinely on uncertain, real time‐varying parameters. A new sufficient condition for the stability of this class of systems, in terms of a feasibility problem involving linear matrix inequalities (LMIs), is obtained under the hypothesis that a bound on the rate of variation of the parameters is known. This condition, obtained by the aid of parameter dependent Lyapunov functions, obviously turns out to be less restrictive than that one obtained via the classical quadratic stability (QS) approach, which guarantees stability in presence of arbitrary time‐varying parameters. An important point is that the methodology proposed in this paper may result in being less conservative than the classical QS approach even in the absence of an explicit bound on the parameters rate of variation. Concerning the synthesis context, the design of a gain scheduled compensator based on the above approach is also proposed. It is shown that, if a suitable LMI problem is feasible, the solution of such problem allows to design an output feedback gain scheduled dynamic compensator in a controller‐observer form stabilizing the class of systems which is dealt with. The stability conditions are then extended to take into account L2 performance requirements. Some numerical examples are carried out to show the effectiveness and to investigate the computational burden required by the proposed approach. Copyright © 2005 John Wiley & Sons, Ltd.
Convective Heat Transfer of an Air Bubble in Water With Variable Thermophysical Properties

A numerical study of convective heat transfer of an air bubble in water with variable thermophysical properties is considered. Two-dimensional simulations of multifluid flows with heat transfer include the Navier–Stokes, energy, and volume of fluid (VOF) advection equations. The solver computes the flow field and temperature by solving the systems of Navier–Stokes equations and the energy equation using the finite–volume method with the SIMPLE algorithm and tracks the position of interface between two fluids with different fluid properties by the VOF method with piecewise linear interface construction technique. Empirical correlations in terms of temperature for thermophysical properties are considered in the simulations. The convective heat transfer model is assessed with a benchmark problem of cooling of water and compared with previous literature data showing good agreement. Finally, a numerical study of the effect of the bubble diameter in the range from 2 mm to 3 mm on heat transfer is performed.
Global annual methane emission rate derived from its current atmospheric mixing ratio and estimated lifetime

Abstract. We use the estimated lifetime of methane (CH4), the current methane concentration, and its annual growth rate to calculate the global methane emission rate. The upper and lower limits of the annual global methane emission rate, depending on loss of CH4 into the stratosphere and methane consuming bacteria, amounts to 648.0 Mt a−1 and 608.0 Mt a−1. These values are in reasonable agreement with satellite and with much more accurate in situ measurements of methane. We estimate a mean tropospheric and mass-weighted temperature related to the reaction rate and employ a mean OH-concentration to calculate a mean methane lifetime. The estimated atmospheric lifetime of methane amounts to 8.28 years and 8.84 years, respectively. In order to improve the analysis a realistic 3D-calculations should be performed.
Versatile cluster based photoelectron spectrometer

A recently constructed cluster based photoelectron spectrometer is described. This instrumentation is unique in that it enables the kinetic energy analysis of electrons ejected from both anions and neutral clusters. This capability permits the investigation of discrete electronic levels in all charge states (anionic, neutral, and cationic). A laser vaporization plasma reactor cluster source affixed with a sublimation cell is employed to produce a variety of metal clusters, and the resulting cluster distributions are analyzed with time-of-flight mass spectrometry. The corresponding electronic structure is analyzed with a “magnetic bottle” photoelectron spectrometer. Examples of instrument performance operating in both anion photodetachment and neutral multiphoton ionization (MPI) modes are provided. In the case of neutral MPI, the corresponding product distribution is collected with a Wiley-McLaren [Rev. Sci. Instrum. 26, 1150 (1955)] mass spectrometer mounted perpendicular to the magnetic bottle photoelec.