Miracle-dz/UniFAR-FTUs huggingface dataset:
Error bounds for quadrature methods involving lower order derivatives

Quadrature methods for approximating the definite integral of a function f(t) over an interval [a,b] are in common use. Examples of such methods are the Newton–Cotes formulas (midpoint, trapezoidal and Simpson methods etc.) and the Gauss–Legendre quadrature rules, to name two types of quadrature. Error bounds for these approximations involve higher order derivatives. For the Simpson method, in particular, the error bound involves a fourth-order derivative. Discounting the fact that calculating a fourth-order derivative requires a lot of differentiation, the main concern is that an error bound for the Simpson method, for example, is only relevant for a function that is four times differentiable, a rather stringent condition. This paper caters for functions for which derivatives exist only of order lower than normally required. A number of quadrature methods are considered and error bounds derived involving only lower order derivatives that can be used depending on the smoothness of the function.
The Lunar Tide in ƒbEs

Hourly measurements of the blanketing frequency of sporadic E(ƒbEs) made during the years 1958 through 1965 have been analyzed for lunar daily variations. The data, which came from ten stations, were analyzed by the Chapman-Miller method. Both seasonal and yearly average lunar variations were obtained. The lunar semidiurnal oscillations in ƒbEs ranged from 0.01 to 0.04 MHz, with maximums occurring from 7 to 9 hours lunar time. The amplitude of the lunar tide in ƒbEs is an order of magnitude less than the lunar variations of ƒ0Es. Since ƒbEs is close to the plasma frequency of Es, the oscillation in ƒbEs represents a lunar variation in the electron density of Es layers, whereas the significance of the lunar variation of ƒ0Es is not clear. The phases of the lunar tides in ƒbEs, ƒ0Es, and h′Es are found to be nearly the same. Two sources of lunar influence on Es electron density are considered (1) wind shears in the lunar tide acting to augment or decrease the wind shears responsible for E8, and (2) interaction of E8 with electrostatic fields associated with the lunar current system.
Thickness-dependent blue shift in the excitonic peak of conformally grown ZnO:Al on ion-beam fabricated self-organized Si ripples

Al-doped ZnO (AZO) thin films of thicknesses 5,10, 15, 20, and 30 nm were deposited on 500 eV argon ion-beam fabricated nanoscale self-organized rippled-Si substrates at room temperature and are compared with similar films deposited on pristine-Si substrates (without ripples). It is observed that morphology of self-organized AZO films is driven by the underlying substrate morphology. For instance, for pristine-Si substrates, a granular morphology evolves for all AZO films. On the other hand, for rippled-Si substrates, morphologies having chain-like arrangement (anisotropic in nature) are observed up to a thickness of 20 nm, while a granular morphology evolves (isotropic in nature) for 30 nm-thick film. Photoluminescence studies reveal that excitonic peaks corresponding to 5–15 nm-thick AZO films, grown on rippled-Si templates, show a blue shift of 8 nm and 3 nm, respectively, whereas the peak shift is negligible for 20-nm thick film (with respect to their pristine counter parts). The observed blue shifts are substantiated by diffuse reflectance study and attributed to quantum confinement effect, associated with the size of the AZO grains and their spatial arrangements driven by the anisotropic morphology of underlying rippled-Si templates. The present findings will be useful for making tunable AZO-based light-emitting devices.
Existence of solutions for a model of multiphase flow in porous media applied to gas migration in underground nuclear waste repository

We prove existence of solutions for a new model of two compressible and partially miscible phase flow in porous media, applied to gas migration in underground nuclear waste repository. This model, modelling fully and partially water saturated situations, consists of a coupled system of quasilinear parabolic partial differential equations. We seek a new set of variables in order to obtain a system which belongs to the class of equations considered by Alt and Luckhaus such that it would be possible to use their existence theorem.
Can flowers provide better spectral discrimination between herbaceous wetland species than leaves?

The identification of species is essential to ecosystem monitoring and assessment. Remote sensing can provide robust and repeatable spectral measurements that are spatially continuous across ecosystems. Typically, the remote sensing of vegetation has relied on the measurement of leaf spectra, or the measurement of mixed spectra that include leaves, flowers and other components such as stems and soils. This study compares the ability to discriminate between species using pure spectra of leaves and flowers using herbaceous vegetation from a prairie fen as a case study. Spectral data of leaves and flowers were collected from 22 species using a handheld spectroradiometer with a spectral resolution of 1 nm from 475 nm to 900 nm. The use of continuous wavelet transformation was explored to enhance detection of shape in the spectral signatures. Due to the inherent high dimensionality of spectroscopy data, a forward feature selection algorithm was used to identify the best sets of individual bands and continuous wavelet transformed features. The results show that flowers consistently provide better species discrimination in spectral space than leaves in terms of both overall discrimination and efficiency (i.e. consistently requiring fewer features to achieve maximum spectral discrimination). For both transformed leaf and flower spectra, most of the selected features were found to be between 500 nm and 600 nm, indicating the importance of this region to differentiate between species when measuring both leaves and flowers. These results indicate the potential to map vegetation using the spectra of flowers as the availability of ultra-high-resolution imagery from low-altitude unmanned aerial remote sensing platforms increases.
Numerical Algorithm for Dynamic Problems Involving Fractional Operators

This paper presents the numerical method for dynamic problems involving fractional operators.Based on Liouville-Riemann's definition of fractional derivatives, the algorithm is developed by incorporating one-step schemes of well-known Newmark types into our own formula.The scheme has the merit of excellent operational characteristics and the simplicity of application.Numerical experiments were given to show the superiority and effectiveness of the algorithm.
Numerical analysis of jet and submerged hydraulic jump using moving particle semi-implicit method

Mesh-free particle (Lagrangian) methods have been used in a wide variety of applications in fluids studies in recent decades. A big advantage of these methods is the ability to model the deformations and spray generation in boundaries and interfaces, which are common problems with jets and jumps and may be difficult using Eulerian methods. Weakly compressible moving particle semi-implicit method (WC-MPS) has been developed and is used in this paper. The model is first validated for jet simulation and then applied to submerged hydraulic jumps. The flow regime, velocity distribution, and turbulence shear stresses at different distances from the jet inlet are investigated and compared with the analytical solution and experimental data. With this method, the inlet flow particles entering the domain can be tracked, as well as the development of vortices and recirculation in the corresponding turbulent flow fields. The comparison of MPS results with experimental data for submerged hydraulic jumps shows the usin.
Differentiated contribution of minerals through soil and foliar fertilization to the winter wheat yield.

Research has evaluated the contribution of minerals through soil and foliar fertilization on winter wheat yield, the purpose being to identify the interdependence relations for the optimization of the fertilization system. Two types of mineral and foliar fertilizers were tested. The complex mineral fertilizer of the type NPK (1:1:1) was used for achieving three differentiated nutrition levels: NPK0, NPK30 (30 kg active substance ha -1 ) and NPK60 (60 kg active substance ha -1 ). There are five types of foliar fertilizers applied and 18 experimental variants were studied. The research was conducted in Soil Science and Plant Nutrition (SSPN) and Mathematics and Statistics (MS), Banat University of Agricultural Sciences and Veterinary Medicine„ Regele Mihai I al României„ from Timisoara, Romania (USAMVBT), between 2011 and 2012. The influence of interaction between the two types of fertilizer compared to their individual influence on wheat production was analyzed. Based on Original Research Article Sala et al.; AJEA, 6(3): 158-167, 2015; Article no.AJEA. 2015.075 159 regression analysis were obtained mathematical model of interdependence, reliability of the results and models have been certified by LSD, p and R 2 (maximum value is better). The complex fertilizers generated yield increase between 925*** and 1425*** kg ha -1 . The foliar fertilizers determined yield increase between 355 and 810*** kg ha with natural soil fertility (NPK0), between 550** and 900*** kg ha -1 with NPK30, and between 500** and 795*** kg ha -1 with NPK60. The yield increase determined by the joint effect of the two types of fertilization was between 1475*** and 2220*** kg ha -1 . The experimental results have high statistical confidence (p<.01; Fcrit<F for Alfa = .01). The study recorded a decrease in the potentiation effect of the foliar fertilizers and at the same time in their contribution to the winter wheat yield, when the doses of complex fertilizers applied on the soil were increased.
Degree-Scale Anisotropy in the Cosmic Microwave Background: SP94 Results

We present results from two observations of the cosmic microwave background (CMB) performed from the South Pole during the 1993-1994 austral summer. Each observation employed a 3 deg peak-to-peak sinusoidal, single-difference chop and consisted of a 20 deg x 1 deg strip on the sky. The first observation used a receiver which operates in three channels between 38 and 45 GHz (Q-band) with a full width half maximum (FWHM) beam which varies from 1 deg to 1.15 deg. The second observation overlapped the first observation and used a receiver which operates in four channels between 26 and 36 GHz (Ka-band) with a FWHM beam which varies from 1.5 deg to 1.7 deg. Significant correlated structure is observed in all channels for each observation. The spectrum of the structure is consistent with a CMB spectrum and is formally inconsistent with diffuse synchrotron and free-free emission at the 5 sigma level. The amplitude of the structure is inconsistent with 20 K interstellar dust; however, the data do not discriminate against flat or inverted spectrum point sources. The root mean square amplitude (+/- 1 sigma) of the combined (Ka + Q) data is Delta T(sub rms) = 41.2(sup +15.5, sub -6.7) micro-K for an average window function which has a peak value of 0.97 at l = 68 and drops to e(exp -0.5) of the peak value at l = 36 and l = 106. A band power estimate of the CMB power spectrum, C(sub l), gives average value of (C(sub l)l(l + 1)/(2 pi))(sub B) = 1.77(sup +1.58, sub -0.54) x 10(exp -10).
Zonal Flow Vacillation and Bimodality of Baroclinic Eddy Life Cycles in a Simple Global Circulation Model

Abstract A global primitive-equation model of the atmosphere is used to study the relationship between the temporal variations of the zonal mean zonal flow and baroclinic eddies. Nonperiodic low-frequency vacillation of the mean zonal flow is found in longtime integrations of the model under a perpetual condition; the zonal-mean jet in the extratropics changes its position nearly barotropically. A potential vorticity–potential temperature (PV–θ) analysis is performed for two extreme periods of the zonal flow vacillation. Anticyclonic breakings of upper troughs are dominant in the period of a high-latitude jet, while cyclonic breakings are dominant in the period of a low-latitude jet. A statistically significant relationship between the zonal flow vacillation and the morphology of life cycles of baroclinic eddies is obtained for the entire period analyzed. An index of the life cycles, which is introduced in this study, shows clear bimodality in its frequency distribution function. The relationship is also .
Evaluating the residual stress in PbTiO3 thin films prepared by a polymeric chemical method

We report a study of residual stress in PbTiO3 (PT) thin films prepared on Si substrates by a polymeric chemical method. The E(1TO) frequency was used to evaluate the residual stress through an empirical equation available for bulk PT. We find that the residual stress in PT films increases as the film thickness decreases and conclude that it originates essentially from the contributions of extrinsic and intrinsic factors. Polarized Raman experiments showed that the PT films prepared by a polymeric chemical method are somewhat a-domain (polar axis c parallel to the substrate) oriented.
Mathematical Modeling and Analysis of Magneto Thermoelastic Plate

Nonlinear equations of thermoelastic plates in an electromagnetic field are developed with consideration of a material nonlinearity. Using the Maxwell equations for an electromagnetic field, the modified Fourier law of heat conduction and elastokinetic field equations, the three-dimensional coupled problem is reduced to a two-dimensional one, appropriate for plates. The existence and uniqueness of the solution of a system of partial differential equations arising from the modeling of current carrying thermoelastic plate-strip in a longitudinal magnetic field is proven.
On the Stochastic Solution to a Cauchy Problem Associated with Nonnegative Price Processes

We consider the stochastic solution to a Cauchy problem corresponding to a nonnegative diffusion with zero drift, which represents a price process under some risk-neutral measure. When the diffusion coefficient is locally Holder continuous with some exponent in (0,1], the stochastic solution is shown to be a classical solution. A comparison theorem for the Cauchy problem is also proved, without the linear growth condition on the diffusion coefficient. Moreover, we establish the equivalence: the stochastic solution is the unique classical solution to the Cauchy problem if, and only if, a comparison theorem holds. For the case where the stochastic solution may not be smooth, we characterize it as a limit of smooth stochastic solutions associated with some approximating Cauchy problems.
Property-Driven Evaluation of RL-Controllers in Self-Driving Datacenters

Reinforcement learning-based controllers (RL-controllers) in self-driving datacenters have evolved into complex dynamic systems that require continuous tuning to achieve higher performance than hand-crafted expert heuristics. The operating environment of these controllers poses additional challenges as it can often change significantly, thus the controllers must be adapted to new external conditions. To obtain trustworthy RL-controllers for self-driving datacenters, it is essential to guarantee that RL-controllers that are trained continuously in these changing environments behave according to the designer’s notions of reliability and correctness. Traditionally, RL-controllers are evaluated by comparing their reward function statistics. However, that does not capture all desired properties, e.g., stability, of the controller. In this work, we propose enhancing the evaluation criteria for RL-controllers with a set of novel metrics that quantify how well the controller performs with respect to user-defined properties. We leverage formal methods for computing our novel metrics. Thus, our work makes a step forward toward improving trustworthiness of RL-controllers. We show that these metrics are useful in evaluating a standalone controller or in comparing multiple controllers that achieve the same reward.
Moire fringes affected by two inclined gratings in Talbot interferometry

A more actual situation is studied on the effects of both inclined grating planes in Talbot interferometry illuminated by a plane wave. In the situation, the two grating planes are first rotated around their own axis parallel to the line direction, and then detector grating is rotated by an angle around the normal of the grating plane. Theoretical analyses indicate that the tilt-angle of the moire fringes is sensitive to the inclination. The results in this paper are also compared with those in one of our earlier works.
Breakdown and defect generation in ultrathin gate oxide

In this work the dielectric reliability of thermally grown ultrathin 3 nm SiO2 layers in poly‐Si/SiO2/Si structures is examined. This is compared with a study of the defect generation in the 3 nm gate oxide during tunnel injection of electrons. In these ultrathin SiO2 layers, direct tunneling of electrons becomes very important. An increase of the direct tunnel and Fowler–Nordheim tunnel current during high‐field stressing was observed and is explained by the creation of a positive charge in the oxide associated with slow interface traps. It is demonstrated that a higher current instability corresponds with a lower charge to breakdown value (QBD) of the oxide. From these results we conclude that the creation of slow interface traps is an important precursor effect for the 3 nm gate oxide breakdown.In this work the dielectric reliability of thermally grown ultrathin 3 nm SiO2 layers in poly‐Si/SiO2/Si structures is examined. This is compared with a study of the defect generation in the 3 nm gate oxide during tunnel injection of electrons. In these ultrathin SiO2 layers, direct tunneling of electrons becomes very important. An increase of the direct tunnel and Fowler–Nordheim tunnel current during high‐field stressing was observed and is explained by the creation of a positive charge in the oxide associated with slow interface traps. It is demonstrated that a higher current instability corresponds with a lower charge to breakdown value (QBD) of the oxide. From these results we conclude that the creation of slow interface traps is an important precursor effect for the 3 nm gate oxide breakdown.
The pursuit of heavy elements in the HgMn-type star Chi Lupi: Observations with the GHRS in the COSTAR ERA

Observations of the ultra-sharp-lined HgMn star chi Lupi made with the Goddard High Resolution Spectrograph after the Hubble Space Telescope First Servicing Mission display the effect of COSTAR corrective optics upon the spectral resolution of several observing modes. The resolution is restored to levels expected in the absence of the telescope spherical aberration for all observations made through the GHRS Large Science Aperture (LSA). The Small Science Aperture (SSA) spectra are nearly identical in resolution to the pre-COSTAR values while benefiting from higher throughput. The line spread function for the LSA relative to the SSA shows little wavelength dependence and reflects a Gaussian profile approximately 20%-30% broader than for SSA spectra. Absorption features containing components of As II and Bi II represent upper limit enhancements of 2.9 and 2.1 dex for As II and Bi II, respectively, relative to meteoritic abundance determinations. (Less)
Trajectories of a DAE near a pseudo-equilibrium

We consider a class of differential-algebraic equations (DAEs) defined by analytic nonlinearities and study its singular solutions. The main assumption used is that the linearization of the DAE represents a Kronecker index-2 matrix pencil and that the constraint manifold has a quadratic fold along its singularity. From these assumptions we obtain a normal form for the DAE where the presence of the singularity and its effects on the dynamics of the problem are made explicit in the form of a quasi-linear differential equation. Subsequently, two distinct types of singular points are identified through which there pass exactly two analytic solutions: pseudo-nodes and pseudo-saddles. We also demonstrate that a singular point called a pseudo-node supports an uncountable infinity of solutions which are not analytic in general. Moreover, akin to known results in the literature for DAEs with singular equilibria, a degenerate singularity is found through which there passes one analytic solution such that the singular point in question is contained within a quasi-invariant manifold of solutions. We call this type of singularity a pseudo-centre and it provides not only a manifold of solutions which intersects the singularity, but also a local flow on that manifold which solves the DAE.
Atmospheric Circulation Features Associated with Rainfall Variability over Southern Northeast Brazil

Abstract The atmospheric circulation features associated with rainfall variability during the main rainy period of the region of southern Northeast Brazil (sNEB) are determined through principal components analysis and cluster analysis. Daily rainfall, NCEP reanalysis, and OLR data are used from 1979 to 1997. The analyses are performed considering a large area including South America and the Pacific and Atlantic Oceans and also considering a regional area over tropical South America. The influence of synoptic systems, as well as the phenomena associated with their variability, such as El Nino–Southern Oscillation (ENSO) and baroclinic waves over the Pacific Ocean and South America are discussed. Positive (negative) rainfall anomalies over sNEB are related to cold (warm) episodes in the tropical Pacific. On the intraseasonal timescale there are interrelationships among the South Atlantic convergence zone (SACZ), Bolivian high, and the northeast upper-cyclonic vortex. It is noted that rainy periods in sNEB .
Geospace Environment Modeling magnetic reconnection challenge: Simulations with a full particle electromagnetic code

The objective of the Geospace Environment Modeling (GEM) magnetic reconnection challenge is to understand the collisionless physics that controls the rate of magnetic reconnection in a two-dimensional configuration. The challenge involves investigating a standard model problem based on a simple Harris sheet configuration by means of a variety of physical models in order to isolate the essential physics. In the present work the challenge problem is modeled using an electromagnetic particle-in-cell code in which full particle dynamics are retained for both electrons and ions and Maxwell's equations are solved without approximation. The timescale for reconnection is of the order of 10 Ωi-1 (where Ωi is the ion cyclotron frequency based on the asymptotic field B0), and the corresponding reconnection electric field is (c/vA)Ey/B0 ∼ 0.24. The diffusion region near the neutral line is observed to develop a multiscale structure based on the electron and ion inertial lengths c/ωpe and c/ωpi. The difference between the ion and electron dynamics in the diffusion region gives rise to in-plane (Hall) currents which produce an out-of-plane By field with a quadrupolar structure. In the diffusion region the magnetic field is no longer frozen-in to the electrons; the inductive Ey field is supported primarily by the off-diagonal electron pressure terms in the generalized Ohm's law. The reconnection rate is found to be insensitive to electron inertia effects and to the presence of a moderate out-of-plane initial field component B0y ≲ B0. The results are consistent with the theory that the reconnection rate is independent of the mechanism which breaks the frozen-in condition and is controlled by dynamics at length scales much greater than the electron dissipation region.
Naturally ordered regular semigroups with maximum inverses

Let S be a regular semigroup. An inverse subsemigroup S° of S is called an inverse transversal if S° contains a unique inverse of each element of S. An inverse transversal S° of S is called multiplicative if x°xyy° is an idempotent of S° for every x, y∈S, where x° denotes the unique inverse of x∈S in S°. In Section 1, we obtain a necessary and sufficient condition in order for inverse transversals to be multiplicative.