Miracle-dz/UniFAR-FTUs huggingface dataset:
Higher order explicit time integration schemes for Maxwell's equations

The finite integration technique (FIT) is an efficient and universal method for solving a wide range of problems in computational electrodynamics. The conventional formulation in time‐domain (FITD) has a second‐order accuracy with respect to spatial and temporal discretization and is computationally equivalent with the well‐known finite difference time‐domain (FDTD) scheme. The dispersive character of the second‐order spatial operators and temporal integration schemes limits the problem size to electrically small structures. In contrast higher‐order approaches result not only in low‐dispersive schemes with modified stability conditions but also higher computational costs. In this paper, a general framework of explicit Runge–Kutta and leap‐frog integrators of arbitrary orders N is derived. The powerful root‐locus method derived from general system theory forms the basis of the theoretical mainframe for analysing convergence, stability and dispersion characteristics of the proposed integrators. As it is clearly stated, the second‐ and fourth‐order leap‐frog scheme are highly preferable in comparison to any other higher order Runge–Kutta or leap‐frog scheme concerning stability, efficiency and energy conservation. Copyright © 2002 John Wiley & Sons, Ltd.
Computation of the Averaged Electric Field in the Semiconductor Obstacle Placed in the Coaxial Line

In this paper we present computed results of the averaged electric field in the semiconductor obstacle placed in the coaxial line. Such layout might be used as a sensor for the measurement of microwave pulse power transmitted through the coaxialline. FDTD (finite different time domain) method was applied for the theoretical investigation. The dependences of the averaged electric field in the obstacle on the microwave frequency, as well as on the dimensions and specific resistance of the obstacle are considered. Both layouts with the obstacle placed on the inner and on the outer conductor of the coaxial line were investigated. Calculations were performed for the 50 Ω impedance coaxial line filled with air and obstacle made from Si.
WAX-ROOM: an indoor WSN-based localization platform

Indoor localization is considered to be a key aspect of future context-aware, ubiquitous and pervasive systems, while Wireless Sensor Networks (WSNs) are expected to constitute the critical infrastructure in order to sense and interact with the environment surrounding them. In the context of developing ambient-assisted living and aftermath crisis mitigation services, we are implementing WAX-ROOM, a WSN specially developed for indoor localization but at the same time able to sense and interact with the environment. Currently, WAX-ROOM incorporates three different localization techniques and an optimal fusion rule. The proposed WSN's architecture and advantages, as well as measurements results regarding its performance in terms of localization accuracy are presented herein, demonstrating the eligibility of the proposed platform for indoor localization.
Method of training examples in solving inverse ill-posed problems of spectroscopy

Further development of the method of computational experiments for solving ill-posed problems is given. The effective (unoverstated) estimate for solution error of the first-kind equation is obtained using the truncating singular numbers spectrum of an operator. It is proposed to estimate the magnitude of the truncation by results of solving model (training, learning) examples close to the initial example (problem). This method takes into account an additional information about the solution and gives a new principle for choosing the regularization parameter and error estimate for equation solution by the Tikhonov regularization method. The method is illustrated by a numerical example from the inverse problem of spectroscopy.
IV. On the elasticity and viscosity of metals

Among the experimental exercises performed by students in the physical laboratory of the University of Glasgow, observations on the elasticity of metals have been continued during many years. Numerous questions of great interest, requiring more thorough and accurate investigation, have been suggested by these observations; and recently they have brought to light some very unexpected properties of metallic wires. The results stated in the present communication are, however, with one or two exceptions, due to the careful experimenting of Mr. Donald Macfarlane, official assistant to the Professor of Natural Philosophy, whose interested and skilful cooperation have been most valuable in almost everything I have been able to attempt in the way of experimental investigation. The subject has naturally fallen into two divisions, Viscosity, and Moduli of Elasticity.
On the derivatives of the collision map of relativistic particles

Abstract Consider a pair of relativistic particles with momenta u and v which collide, emerging with new momenta u' and v'. The collision map (u,v) → (u',v') is studied for a fixed scattering direction w. The Jacobian is given explicitly, and it is shown that the average over the scattering directions of the derivatives of this map is bounded in one of the variables u, v.
Motion control of single F1-ATPase rotary biomolecular motor using microfabricated local heating devices

Biomolecular motors are major targets in single-molecule studies, which reveal molecular behaviors usually hidden in the emsemble- and time-averaging of bulk experiments. Methods for rapid experimental condition control during single-biomolecule observation are a key technology to elucidate the molecular mechanisms of proteins. One of the most promising methods is real-time rapid temperature alternation. A microheater and a microthermosensor were integrated on the glass plate for controlling the temperature locally; the maximum response speeds were 71.5 and 56.9K∕s for temperature rise and fall, respectively. Rapid temperature alternation with microfabricated thermodevice allowed rapid and reversible angular velocity control of a single F1-ATPase, a rotary biomolecular motor. The rapid control of the temperature enabled us to perform rotation assay at temperatures higher than that would “normally” denature them. This revealed that the torque of F1-ATPase seems to increase at higher temperatures with the i.
Adolescent girls’ perceptions of breastfeeding in two low-income periurban communities in South Africa

Abstract In South Africa, exclusive breastfeeding rates are low, and rates of teenage pregnancy are high. Educational policy enables mothers’ return to school, which conflicts with policy emphasizing exclusive breastfeeding. We elicited adolescent women’s perceptions and experiences of infant feeding choices, and conducted six focus groups (N = 57) in two periurban settlements. Participants knew arguments in favor of and against breast and formula-feeding, but in practice, mixed feeding occurred early after birth. While completion of high school was emphasized, exclusive breastfeeding was viewed as impractical. Congruent education policies and infant feeding policies/guidelines must address the constraints and contexts of adolescent mothers.
Directional sinogram inpainting for limited angle tomography

In this paper we propose a new joint model for the reconstruction of tomography data under limited angle sampling regimes. In many applications of tomography, e.g. electron microscopy and mammography, physical limitations on acquisition lead to regions of data which cannot be sampled. Depending on the severity of the restriction, reconstructions can contain severe, characteristic, artefacts. Our model aims to address these artefacts by inpainting the missing data simultaneously with the reconstruction. Numerically, this problem naturally evolves to require the minimisation of a non-convex and non-smooth functional so we review recent work in this topic and extend results to fit an alternating (block) descent framework. We perform numerical experiments on two synthetic datasets and one electron microscopy dataset. Our results show consistently that the joint inpainting and reconstruction framework can recover cleaner and more accurate structural information than the current state of the art methods.
Formation of OB Associations in Galaxies

We consider the formation of OB associations from two perspectives: (1) the fractional gas consumption in star formation, ϵ, per dynamical timescale tdyn in a galaxy, and (2) the origin of the so-called Kennicutt-Schmidt law, that the rate of star formation per unit area is proportional to a power, α, of the surface density in H I and H2 gas when certain thresholds are crossed. The empirical findings that ϵ ≈ 10-2 and α ≈ 1.4 or 1.5 have simple explanations if the rate of star formation is magnetically regulated. An empirical test of the ideas resides in an analysis of why giant OB associations are "strung out like pearls along the arms" of spiral galaxies.
Failure Mechanism of Anti-Inclined Karst Slope Induced by Underground Multiseam Mining

There occurred a lot of catastrophic landslides in Southwest China karst areas in recent years. This study numerically simulated the failure process of Pusa landslide by distinct element method (UDEC). The Voronoi diagram algorithm was used to discretize the rock blocks in the upper part of the mining area, and the erosion in sliding source area caused by heavy rainfall was simulated by increasing the block density and reducing the joint strength. Results obtained using UDEC matched the failure process recorded by UAV, and the subsidence of monitoring points on the slope surface was well coincident with the InSAR results. The DEM results are as follows: firstly, under the action of underground coal mining, the overlying strata of the mountain deform toward the goaf and the deformation of the stratum increase significantly with the caving of the roof stratum; and the deep karst fissures in the overlying stratum have an important influence on the deformation of the mountain; the upper strata form a subsidence zone along the fissures, expanding the range of tensile fissures. Secondly, due to the excavation and unloading of the rock masses at the leading edge of the sliding area, the extrusion deformation occurs to the outside of the slope, resulting in the critical instability of sliding area. Finally, with the strength decreasing of rock masses and structural planes by heavy rainfall, the stability of the mountain continues to decrease until the sliding area collapses.
Observations of the C-13 isomers of cyanoacetylene - implications for carbon isotope studies in the Milky Way

Observations of the J = 1 to 0 rotational transitions of HC3N, H(C-13)CCN, HC(C-13)CN, and HCC(C-13)N in the Galactic molecular cloud Sgr B2 have been analyzed. No evidence for fractionation is found in the three C-13 isomers. The results support the suggestion that the HC3N J = 1 to 0 transition is a weak maser in Sgr B2. A C-12/C-13 ratio of 11 + or - 2 is obtained for Sgr B2. 31 references.
Semidirect Products of Monoidal Categories

We introduce semidirect products of skew monoidal categories as a categorification of semidirect products of monoids (or, perhaps more familiarly, of groups). We also discuss how this construction interacts with monoidal, autonomous and closed monoidal structures. We end by producing some examples of monoidal categories which are left closed but not right closed.
Glycerol and Temperature Effects on Mechanical Properties of Biodegradable Plastic from Rice Four with Rice Husk Filler

Biodegradable plastics were fabricated from rice flour by the extrusion method using glycerol and rice husk powder as the plasticizer and filler, respectively. The independent variables were temperature (100 − 120  C), glycerol (25 − 45%), and rice husk powder (0 − 20%). The independent variables were varied at three levels following the Box-Behnken experimental design. Three response surface models describing the effect of the independent variables on the tensile strength, elongation at break, and stiffness of the plastics were proposed. The tensile strength and the elongation at the break of the plastics were significantly affected by glycerol and rice husk, while the stiffness of the plastic was only significantly influenced by glycerol. The response optimizer was applied to estimate the optimum conditions for preparing the plastics, i.e., 100  C for temperature, 25.81% for glycerol, and 0% for rice husk. The tensile strength, elongation at break, and stiffness of the plastic estimated by the optimum conditions were 7.27 MPa, 12.45%, and 10630 N/m, respectively. The biodegradable plastics prepared with the optimum conditions had a tensile strength of 7.13 MPa, elongation at break of 13.05%, and stiffness of 10400 N/m. These values are closely similar to the predicted values.
ACCRETION DISC DYNAMOS IN THE PRESENCE OF A WEAK EXTERNAL MAGNETIC FIELD

We consider the problem of an MHD dynamo operating in a thin accretion disc vertically threaded by a uniform external magnetic field. Axisymmetric, two-dimensional models corresponding to the so-called standard a-disc and to the fiducial protoplanetary disc powered by turbulent viscous stress are calculated. The geometry of the total field lacks equatorial symmetry as the generated field, having a quadrupole symmetry, is superposed on an external field having a dipole symmetry. The degree of this asymmetry depends on the magnitude of the generated field relative to the externally imposed field. The existence of an external field makes it possible for some otherwise closed field lines to open. Owing to the intrinsic asymmetry of the solution, open field lines emerging from the top and the bottom surfaces of a disc are inclined in a different sense with respect to the vertical. This may be pertinent to the problem of asymmetric or one-sided jets seen among AGNs and protostars.
Magnetic vortex wall motion driven by spin waves

A magnetic vortex wall motion driven by propagating spin waves in a nanostrip is investigated by means of micromagnetic simulation. Propagating spin waves can drive a vortex wall into a stream motion in spite of its complex internal spin structure. Compared to the transverse wall, the vortex wall moves faster and its velocity is less sensitive to the spin wave frequency. The amplitude of spin waves changes when passing through the domain wall, closely related to the domain wall velocity. This domain-wall-type-specific study provides important information for developing the theory of the interaction between domain wall and spin waves.
Bayesian calibration of computer models

We consider prediction and uncertainty analysis for systems which are approximated using complex mathematical models. Such models, implemented as computer codes, are often generic in the sense that by a suitable choice of some of the model's input parameters the code can be used to predict the behaviour of the system in a variety of specific applications. However, in any specific application the values of necessary parameters may be unknown. In this case, physical observations of the system in the specific context are used to learn about the unknown parameters. The process of fitting the model to the observed data by adjusting the parameters is known as calibration. Calibration is typically effected by ad hoc fitting, and after calibration the model is used, with the fitted input values, to predict the future behaviour of the system. We present a Bayesian calibration technique which improves on this traditional approach in two respects. First, the predictions allow for all sources of uncertainty, including the remaining uncertainty over the fitted parameters. Second, they attempt to correct for any inadequacy of the model which is revealed by a discrepancy between the observed data and the model predictions from even the best‐fitting parameter values. The method is illustrated by using data from a nuclear radiation release at Tomsk, and from a more complex simulated nuclear accident exercise.
Four-Dimensional Data Assimilation in the Monsoon Region. Part I: Experiments with Wind Data

Abstract A limited primitive equation model has been used to study the feasibility of four-dimensional data assimilation in the monsoon region and, further, to study the applicability of several assimilation techniques currently being employed in global models. The two fundamental objectives of this research are (i) to understand how the model atmosphere responds to the insertion of asynchronous data and its impact on the assimilation-prediction cycle, and (ii) to determine what assimilation strategies work best for limited-area models in the tropics. A sequence of ten assimilation experiments are performed using different update procedures; all insertions are carried out with only the wind observations. The model is initialized with the ECMWF FGGE level III-b data for the onset vortex case of 17 June 1979, and assimilations are carried out using the summer MONEX level II-b data during the first 12 hours. From these assimilated states, 24-h forecasts are then made. The results lend support to the premise .
On the construction of fuzzy preference structures

In this paper, we analyse the generalization of the classical method of the construction of a preference structure from a reflexive binary relation to the case of fuzzy binary relations. According to our approach, there are two interesting fuzzy preference structures we can construct from a given reflexive fuzzy binary relation. These two fuzzy preference structures correspond to the two extreme solutions of the system of functional equations in the method of Fodor and Roubens. We also prove that only one of two fuzzy preference structures allows its fuzzy relation of strict preference to be transitive with respect to the φ-transform of the Lukasiewicz t-norm when the reflexive fuzzy relation it is constructed from is also transitive with respect to the same t-norm. © 1998 John Wiley & Sons, Ltd.
Successful Starshade petal deployment tolerance verification in support of NASA’s technology development for exoplanet missions

A Starshade is a sunflower-shaped satellite with a large inner disk structure surrounded by petals. A Starshade flies in formation with a space-borne telescope, creating a deep shadow around the telescope over a broad spectral band to permit nearby exoplanets to be viewed. Removing extraneous starlight before it enters the observatory optics greatly loosens the tolerances on the telescope and instrument that comprise the optical system, but the nature of the Starshade dictates a large deployable structure capable of deploying to a very precise shape. These shape requirements break down into key mechanical requirements which include the rigid-body position and orientation of each of the petals that ring the periphery of the Starshade. To verify our capability to meet these requirements, we modified an existing flight-like Astromesh reflector, provided by Northrup Grumman, as the base ring to which the petals attach. The integrated system, including 4 of the 30 flight-like subscale petals, truss, connecting spokes and central hub, was deployed tens of times in a flight-like manner using a gravity compensation system. After each deployment, discrete points in prescribed locations covering the petals and truss were measured using a highly-accurate laser tracker system. These measurements were then compared against the mechanical requirements, and the as-measured data shows deployment accuracy well within our milestone requirements and resulting in a contrast ratio consistent with exoplanet detection and characterization.
Computer-generated holograms of tilted planes by a spatial frequency approach

Computer-generated holograms of plane surfaces tilted and shifted with respect to the hologram plane are considered. The analysis is made in the spatial frequency domain by using the translation and rotation transformations of angular spectra. The frequency approach permits the use of the fast-Fourier-transform algorithm, which decreases the computation time and makes it possible to consider any position of the planes in space. Various configurations of tilted and shifted planes have been investigated, and computer-generated holograms of off-axis planes have been obtained. Computer and optical reconstructions, both of which show the feasibility of the proposed approach, have been carried out.
“1D+4DVAR” Assimilation of NCEP Stage-IV Radar and Gauge Hourly Precipitation Data at ECMWF

Abstract The one- plus four-dimensional variational data assimilation (“1D+4DVAR”) method currently run in operations at ECMWF with rain-affected radiances from the Special Sensor Microwave Imager is used to study the potential impact of assimilating NCEP stage-IV analyses of hourly accumulated surface precipitation over the U.S. mainland. These data are a combination of rain gauge measurements and observations from the high-resolution Doppler Next-Generation Weather Radars. Several 1D+4DVAR experiments have been run over a month in spring 2005. First, the quality of the precipitation forecasts in the control experiment is assessed. Then, it is shown that the impact of the assimilation of the additional rain observations on global scores of dynamical fields and temperature is rather neutral, while precipitation scores are improved for forecast ranges up to 12 h. Additional 1D+4DVAR experiments in which all moisture-affected observations are removed over the United States demonstrate that the NCEP stage-IV.
Viscosity and the chew-goldberger-low equations in the solar corona

A general discussion of the dominant terms in the stress tensor in a magnetized plasma such as the solar corona is presented. The importance of dissipative terms such as electrical resistivity, heat conduction, and interspecies collisions is assessed. For average coronal conditions, the proton stress tensor is found to reduce to the dominant terms in the classical expression for the viscous stress. The classical expression can fail in the transition region, however. In the diffusion region of reconnection, classical viscosity will be appropriate if the resistivity is very large, so that the diffusion region is broad, but in that case the viscous heating is small compared to the resistive heating. On the other hand, the more general expression for the stress tensor is required if the diffusion region is thin; the stress tensor will be important in this case. The electron stress tensor is also considered, and it is shown how the classical expression for electron viscosity can fail in the transition region and lower corona. 14 references.