Miracle-dz/UniFAR-FTUs huggingface dataset:
On the reinitialization procedure in a narrow‐band locally refined level set method for interfacial flows

A local level set algorithm for simulating interfacial flows described by the two‐dimensional incompressible Navier–Stokes equations is presented. The governing equations are solved using a finite‐difference discretization on a Cartesian grid and a second‐order approximate projection method. The level set transport and reinitialization equations are solved in a narrow band around the interface using an adaptive refined grid, which is reconstructed every time step and refined using a simple uniform cell‐splitting operation within the band. Instabilities at the border of the narrow band are avoided by smoothing the level set function in the outer part of the band. The influence of different PDE‐based reinitialization strategies on the accuracy of the results is investigated. The ability of the proposed method to accurately compute interfacial flows is discussed using different tests, namely the advection of a circle of fluid in two different time‐reversed vortex flows, the advection of Zalesak's rotating disk, the propagation of small‐amplitude gravity and capillary waves at the interface between two superposed viscous fluids in deep water, and a classical test of Rayleigh–Taylor instability with and without surface tension effects. The interface location error and area loss for some of the results obtained are compared with those of a recent particle level set method. Copyright © 2005 John Wiley & Sons, Ltd.
Knowledge obstacles when transitioning towards circular economy: an industrial intra-organisational perspective

Circular economy (CE) is necessary for achieving sustainability goals. Nonetheless, the distillation of CE practices into business operations has been unsatisfactory as firms struggle to transition to CE. There is an increase in studies that have attempted to identify challenges impeding the implementation of CE practices. However, most of these studies focus on technical and external aspects affecting CE, leaving intra-organisational aspects such as organisational learning and knowledge largely unexplored. The latter aspects can play a significant role in CE transitions, and thus warrants further research. To address this research gap, this study draws on lean thinking as an organisational learning system and accentuates knowledge obstacles, seen as wastes, that can stifle a transition to CE. Subsequently, it deploys action-learning research, involving collaboration between researchers and the participants in the action to generate actionable knowledge. The analysis of the findings is used to develop a novel framework including six measures that can be implemented to counteract knowledge obstacles and lay a foundation for a CE transition. The proposed framework can be the basis for further research on lean and intra-organisational aspects that can help firms restructure the current linear mode of production, and thus accelerate a smooth CE transition.
The evolution of Red Supergiants at very low metallicity

Red supergiants (RSG) are a crucial phase in the evolution of massive stars. At solar metallicity, they represent the stage where substantial amounts of mass and angular momentum are lost. Here we investigate the role of RSGs at very low metallicity. We have computed evolutionary tracks at Z=0.0004 with and without rotation, using the latest version of the Geneva stellar evolution code. Here, we briefly discuss the evolution of RSGs, their lifetimes, mass ranges for forming RSGs, maximum luminosity of RSGs, and how these are affected by rotation.
Synthetic colourants in capsule dietary supplements on the Korean market

ABSTRACT This study developed a rapid and easy analytical method for the simultaneous determination of nine synthetic colourants (SCs) in capsule dietary supplements. Sample pretreatment involved thermal treatment to dissolve gelatin, using the enzymes protease and amylase to prevent the gelation of gelatin and fat-soluble substances removal using petroleum ether. The method was linear (r 2 ≥0.999), with LOD of 0.009–0.029 μg/mL and LOQ of 0.42–1.40 μg/g. Recovery ranged from 90.9 to 108.9%. The relative expanded measurement uncertainty ranged from 4.1 to 6.3%. Allura Red AC (R40) and Brilliant Blue FCF (B1) were commonly detected in 20 of the 28 samples. Up to six SCs such as Tartrazine (Y4), Sunset yellow (Y5), Amaranth (R2), Erythrosine B (R3), R40 and B1 were detected in a single sample, ranging from 30.5 to 40.2 μg/g. Total content of SCs in various capsule supplements ranged from 0.3 to 73.7 μg/g.
Sea-Ice in Twentieth-Century Simulations by New MIROC Coupled Models: A Comparison between Models with High Resolution and with Ice Thickness Distribution

Sea ice has a large impact on climatic system and its variability. A good reproducibility of the past state of the sea ice in global climate models will reduce uncertainty in future projection. Here, we present sea-ice simulations for new versions of atmosphere-ocean coupled general circulation models, the Model for Interdisciplinary Research on Climate version 4h (MIROC4h) and version 5 (MIROC5), and assess the reproducibility of the sea ice prior to the future projection. The horizontal resolution of MIROC4h is signiﬁcantly high for a coupled climate model, although its sea-ice component is based on the previous version. MIROC5 employs some improved schemes including subgrid-scale ice thickness distribution. Hindcast simulations of twentieth-century climate by the new models are compared with observations and with the results of previous versions of MIROC. For the Northern Hemisphere, Arctic sea-ice simulations are improved in both MIROC4h and MIROC5 compared with previous models. MIROC5 generally agrees well with observational data, whereas in MIROC4h, the Arctic sea ice is smaller in summer extent and in thickness. Employment of the ice thickness distribution, which allows large heat exchange through subgrid-scale thin ice regardless of the grid-averaged thickness, and relatively high albedo parameters contribute to reproduce more realistic ice thickness in MIROC5 compared with that in MIROC4h. For the Southern Hemisphere, MIROC4h well reproduces the observed ice edge, especially in winter, while MIROC5 underestimates sea-ice extent. Both models indicate decreasing trends in Arctic sea ice in the late twentieth century. A heat budget analysis of the MIROC5 Arctic Ocean suggests that intensiﬁcation of ice-albedo feedback accelerates the rate of Arctic ice decline.
3D object recognition from range images using transform invariant object representation

3D object recognition is performed using a scale and orientation invariant feature extraction method and a scale and orientation invariant topological representation. 3D surfaces are represented by sparse, repeatable, informative and semantically meaningful 3D surface structures, which are called multiscale features. These features are extracted with their scale (metric size and resolution) using the classified scale-space of 3D surface curvatures. Triplets of these features are used to represent the surface topologies invariant to transformation (scaling, rotation, translation) and geometric hashing is used for object recognition. Scaled and both scaled and occluded versions of range images from a 3D object database are tested and the experimental results are compared with other methods in the literature.
Seawater pH sensor based on the long period grating in a single-mode-multimode-single-mode structure

A pH sensor is developed based on the long-period grating (LPG) inscribed into a single-mode–multimode–single-mode (SMS) structure in order to measure the pH in seawater. The LPG is formed by using a focused CO 2 laser at LPG's critical period (1 mm). The transmission characteristics are similar to that of a multimode fiber. However, the SMS structure has a higher sensitivity because mode coupling only happens between the fundamental mode and higher-order modes in the SMS structure. The pH-sensitive hydrogel is made by the thermal cross-link of poly vinyl alcohol and poly acrylic acid. This sensor has been utilized in seawater pH sensing in the range of 6–8. Experiments have confirmed that the sensor is sensitive and repeatable.
Underwater Acoustic Sensor Using Optical Fiber Bragg Grating as Detecting Element

An underwater acoustic sensor using an optical fiber Bragg grating (FBG) in the reflection mode is examined to characterize the sensor under various conditions. For the fabrication of the sensor, one end of the FBG fiber pigtail is terminated by a low reflection facet such as an APC connector or an angled cut fiber and the output signal is extracted by an optical circulator of low back reflection. The sensor demonstrated as good performance of fundamental characteristics as a FBG acoustic sensor in the transmission mode. Considering many of the basic properties such as sensitivity, linearity, frequency response and compactness, an acoustic sensor using a FBG is as good as or better than a conventional PZT acoustic sensor.
Comparison of Sampling Methods for Dynamic Stochastic Programming

In solving a scenario-based dynamic (multistage) stochastic programme scenario generation plays a critical role, as it forms the input specification to the optimization process. Computational bottlenecks in this process place a limit on the number of scenarios employable in approximating the probability distribution of the paths of the underlying uncertainty. Traditional scenario generation approaches have been to find a sampling method that best approximates the path distribution in terms of some probability metrics such as minimization of moment deviations or Wasserstein distance. Here, we present a Wasserstein-based heuristic for discretization of a continuous state path probability distribution. The chapter compares this heuristic to the existing methods in the literature (Monte Carlo sampling, moment matching, Latin hypercube sampling, scenario reduction, and sequential clustering) in terms of their effectiveness in suppressing sampling error when used to generate the scenario tree of a dynamic stochastic programme. We perform an extensive computational investigation into the impact of scenario generation techniques on the in-sample and out-of-sample stability of a simplified version of a four-period asset–liability management problem employed in practice (Chapter 2, this volume). A series of out-of-sample tests are carried out to evaluate the effect of possible discretization biases. We also attempt to provide a motivation for the popular utilization of left-heavy scenario trees based on the Wasserstein distance criterion. Empirical results show that all methods outperform normal MC sampling. However, when evaluated against each other these methods essentially perform equally well, with second-order moment matching showing only marginal improvements in terms of in-sample decision stability and out-of-sample performance. The out-of-sample results highlight the problem of under-estimation of portfolio risk which results from insufficient samples. This discretization bias induces overly aggressive portfolio balance recommendations which can impair the performance of the model in real-world applications. Thus this issue needs to be carefully addressed in future research, see e.g. Dempster et al. (2010).
Senior Seminar: Across a Department and Across The Years

Abstract The Department of Mathematics at Bates College has offered a senior seminar capstone course for over a dozen years. In this article, we discuss the coexistence of seminar and thesis, our other capstone experience. We discuss in detail the goals of our seminar, various ways we structure the seminar to accomplish those goals, and methods of assessment. We provide a detailed look into a recent seminar, and we offer a variety of strategies for implementing such a capstone course successfully.
Adhesive bonding in microelectronics and photonics

The use of adhesive bonding in joining of materials with different characteristics is of major importance in a variety of microelectronic and photonic applications. The curing of such adhesives is also of great consequence, with the use of optical radiation for adhesive curing becoming the method of choice in various applications, especially bonding of components in microelectronics and fiber–optic assembly. This article reviews recent advances in the development of adhesives, their applications, and their curing methods using optical radiation; it also includes a brief overview of the adhesion mechanisms.
Distances for galactic planetary nebulae using mean forbidden [O II] doublet ratio electron densities

[O II] 3726, 3729-A doublet ratios and electron densities are presented for 68 galactic planetary nebulae (PN). For 45 of the objects, the doublet ratios represent integrations over the whole of the nebula. Distances have been derived for the majority of the nebulae, using calibrations recently derived from Magellanic Cloud PN. For PN which are optically thin in the hydrogen Lyman continuum, distances have been derived using a variant of the Shklovsky method (constant ionized hydrogen mass) which uses the mean [O II] electron density and the measured radio flux and which does not require knowledge of the filling factor or nebular angular radius
Effects of electron structure and multielectron dynamical response on strong-field multiphoton ionization of diatomic molecules with arbitrary orientation: An all-electron time-dependent density-functional-theory approach

We present a time-dependent density-functional-theory approach for the ab initio study of the effect of correlated multielectron responses on the multiphoton ionization (MPI) of diatomic molecules ${\text{N}}_{2}$, ${\text{O}}_{2}$, and ${\text{F}}_{2}$ in intense short laser pulse fields with arbitrary molecular orientation. We show that the contributions of inner molecular orbitals to the total MPI probability can be significant or even dominant over the highest-occupied molecular orbital, depending on detailed electronic structure and symmetry, laser field intensity, and orientation angle.
The Temperature-Jump Effect and the Theory of the Thermal Boundary Layer for a Spherical Resonator. Speeds of Sound in Argon at 273.16K

The theory of the thermal boundary layer at the walls of a spherical acoustic resonator is discussed in detail. For gases at low pressures, the temperature-jump effect is found to make a significant contribution to the resonance frequencies of the radial modes but not to their acoustic losses. Experimental results are reported for argon at 273.16 K and pressures between 15 and 248 kPa, and compared with the theory. These were obtained using the four radial modes with lowest frequency of a spherical resonator with a radius of 60 mm. The thermal accommodation coefficient between argon and the aluminium wall of the resonator was found to be (0.84 ± 0.05). The results suggest that a determination of the gas constant with a fractional imprecision of 1 × 10-5 or better should be possible using a spherical acoustic resonator.
Protostellar Cosmic Rays and Extinct Radioactivities in Meteorites

Calcium-aluminum-rich inclusions (CAIs) and chondrules of chondritic meteorites may originate with the melting of dustballs launched by a magnetically driven bipolar outflow from the inner edge of the primitive solar nebula. Bombardment by protostellar cosmic rays may make the rock precursors of CAIs and chondrules radioactive, producing radionuclides found in meteorites that are difficult to obtain with other mechanisms. Reasonable scalings from the observed hard X-rays for the cosmic-ray protons released by flares in young stellar objects yield the correct amounts of 41Ca,53Mn, and 138La inferred for meteorites, but proton- and α-induced transformations underproduce 26Al by a factor of about 20. The missing 26Al may be synthesized by 3He nuclei accelerated in impulsive flares reacting primarily with 24Mg, an abundant isotope in the target precursor rocks. The mechanism allows a simple explanation for the very different ratios of 26Al/27Al inferred for normal CAIs, CAIs with fractionated and unidentified nuclear (FUN) anomalies, and chondrules. The overproduction of 41Ca by analogous 3He reactions and the case of 60Fe inferred for eucritic meteorites require special interpretations in this picture.
Interferometric examination of the effect of bending on some single-mode fibre parameters

The numerical aperture, the acceptance angle, the dispersion per unit length and the modal dispersion are important parameters in optical fibre characterization. Optical anisotropy produced in fibres undergoing bending gives valuable information for the characterization of these fibres. The present work provides a sensitive and analytical new technique to examine the influence of bending on single-mode optical fibres measuring, with a high spatial resolution, the radial changes in the previous fibre parameters due to bending. Multiple-beam Fizeau fringes crossing perpendicularly a bent fibre immersed in a matching silvered liquid wedge have been used successfully to determine the variation in the fibre index profile as a function of the fringe shift with accuracy 1 × 10−4. Mathematical expressions are given utilizing the measured fringe shift to characterize the bent fibre and to determine its radial parameter profiles.
Spectral energetics of the observed and simulated Northern Hemisphere general circulation during blocking episodes

Abstract The spectral energetics of the Northern Hemisphere circulation during blocking episodes of the FGGE year is investigated with gridded analyses of observational data and Parallel simulation experiments. The purpose of this study is to describe the energetics distinctions of the observed and simulated blockings in the context of the general circulation and to assess the capability of the model to simulate blockings. In the observed circulation a pronounced winter blocking is developed and maintained by the nonlinear wave-wave interaction L(1) from the kinetic energy source for n = 3–10, where L(n) is the transfer of eddy kinetic energy from all other wavenumbers to wavenumber n. In the case of the. double blocking in the winter, both L(1) and L(2) support the blocking. The kinetic energy source of n=3–10 for upscale input at n = 1 and 2 is supported by the baroclinic conversion at n3–10. The simulated winter circulation shows strong baroclinic conversion at all wavenumbers, including ultralong wave.
Low frequency studies of the Galactic Centre with GMRT

We have observed the GC region at 255 and 154 MHz with the GMRT. From the 255 MHz map we detect 28 compact sources, and an anti-correlation of their deconvolved sizes with angular distance from the GC is observed. This is the first direct indication of scatter broadening for a statistically large sample of extragalactic sources in the region and we discuss its implications in determining the properties of the screen. Our multifrequency observations at 255 and 154 MHz in tandem with previous observations of the GC shows that the 7' halo in Sgr A complex is a non-thermal source rather than a mixture of thermal and non-thermal electrons as was proposed before.
Modularised fast polynomial transform algorithms for two-dimensional digital signal processing

Novel, modularised, fast polynomial transform (FPT) algorithms for computing 2-D convolutions and 2-D discrete Fourier transforms are presented. In these new methods, only fast polynomial transforms, fast Fourier transforms and number theoretic transforms of the same length are required. Consequently the modularity and regularity of the proposed algorithms make them of great practical value in the concurrent implementation of the parallel-pipeline FPT for 2-D digital signal-processing tasks.
Accuracy of the tight binding approximation for the description of the photonic crystal coupled cavities

Coupled optical cavities are constantly attracting increased attention in telecommunication applications. For an infinite chain of optical cavities, also known as the coupled resonator optical waveguide (CROW), the tight binding approximation has been used in order to evaluate its dispersion characteristics and the modal fields. In this paper, the accuracy of the tight binding formalism is investigated for a finite chain of optical cavities of arbitrary length. This approximation allows the derivation of simple analytical formulas for the resonant frequencies and the corresponding modal fields, which involve only the resonant frequency of the isolated cavity and the coupling coefficients between two consecutive coupled cavities. The equations for the modal fields involve an expansion in terms of displaced versions of the field distribution of the mode of the isolated cavity and simple trigonometric functions. These analytical results are compared with the numerical results of the plane wave expansion method in the case of a finite photonic crystal chain of coupled resonators and an excellent agreement is observed even if the cavities are placed close together. The results clearly indicate the usefulness and accuracy of the tight binding formalism for the description of coupled optical resonators.
Photo-Thermal Measurement of Absorptance Losses , Temperature induced Wavefront Deformation and Compaction in DUV-Optics

A measurement system for quantitative registration of transient and irreversible lens effects in DUV optics induced by absorbed UV laser radiation was developed at the Laser-Laboratorium Göttingen. It is based upon a strongly improved Hartmann-Shack wavefront sensor with an extreme sensitivity of ~λ/10000 RMS @ 193nm, accomplishing precise online monitoring of wavefront deformations of a collimated test laser beam transmitted through the laser-irradiated site of a sample. Caused by the temperature dependence of the refractive index as well as thermal expansion and compaction, the initially plane wavefront of the test laser is distorted into a convex or concave lens, dependent on sign and magnitude of index change and expansion. The observed wavefront distortion yields a quantitative measure of the absorption losses in the sample. Some results for fused silica and CaF2 are presented.
A Finite Element Method Code to Analyse Waveguide Dispersion

The aim of our current work is to construct an algorithm for solving problems of radiation and detection of transient electromagnetic waves in the analysis of permeable bodies. The Time-Domain Finite Element Method (TDFEM) will be used in combination with other numerical techniques. TDFEM is necessary to design — with good precision — the broadband antennas to be used. Here we report the first step achieved in this goal. We designed a Finite Element Method (FEM) code to solve two-dimensional static problems in homogeneous waveguides. In order to test the algorithm constructed, it was applied to calculate dispersion features and to obtain the electromagnetic field in the transversal section of the waveguides for the propagation modes. The results obtained are in good agreement with the analytical results and those of other authors. Currently, we are developing a more complete code that includes time (TDFEM) and that focuses on three-dimensional problems.