Miracle-dz/UniFAR-FTUs huggingface dataset:
Development of a SERS optode for the in-situ detection of chemicals in sea water

The purpose of this work is the development of a method for the in-situ detection of chemicals in sea water. Raman scattering was chosen as it is a non-intrusive method yielding finger-printing spectra of the analytes. Surface-enhanced Raman scattering (SERS) is used to provide the sensitivity necessary for trace analysis in the environment. SERS active coatings are produced by encapsulating a silver colloid in sol-gel derived xerogel films. The sol is coated onto silicon plates, microscope slides, quartz windows or optical fibers allowing a variety of measurement configurations. Results are presented for a range of aromatic hydrocarbons in sea water measured with methyl triethoxy silane (MTEOS) and ethyl triethoxy silane (ETEOS) based substrates. The suitability for operation in the marine environment is discussed in terms of selectivity, response time, limits of detection, and long term stability. Two compact marinised optodes are presented with a lensed head and a fiber head allowing for in-situ measurements in sea water with exchangeable SERS substrates or coated fibers. The optode is linked via optical fibers to an underwater core instrument containing light source and spectrograph. This is discussed in the context of a multi- disciplinary field-operable measuring device intended for operation depths up to 300 m.
Exact Occupation Kinetics for One‐Dimensional Arrays of Dumbbells

By utilizing a branch‐dependent counting technique, exact relationships are developed which describe the ensemble average of the kinetics of occupation by dumbbells of finite one‐dimensional arrays of compartments. It is shown that, as the number of compartments per array tends to infinity, 〈θ(t)〉, the ensemble average of the fraction of an array which is occupied, is given by 〈θ(t)〉=1−exp{−2[1−exp(−vt)]}, where v is the striking frequency and t is time. By contrasting these results with the statistics of one‐dimensional arrays of dumbbells, it is demonstrated that it is inappropriate to employ classical statistical‐mechanical methods (e.g., the Bethe approximation) to treat the kinetic aspects of occupation where configurational correlation exists. (Here we define configurational correlation to be the situation in which the occupation of a compartment precludes the occupation of one of its nearest neighbors.)
Des Vents et des Jets Astrophysiques

L'ejection continue de plasma autour d'objets massifs est un phenomene largement repandu en astrophysique, que ce soit sous la forme du vent solaire, de vents stellaires, de jets d'etoiles en formation, de jets stellaires autour d'objets compacts ou de jets extra-galactiques. Cette zoologie diversifiee fait pourtant l'objet d'un commun effort de modelisation. Le but de cette revue est d'abord de presenter qualitativement le developpement, depuis leur origine, des diverses theories de vents (Partie 1) et l'inter disciplinarite dans ce domaine. Il s'agit d'une enumeration, plus ou moins exhaustive, des idees proposees pour expliquer l'acceleration et la morphologie des vents et des jets, accompagnee d'une presentation sommaire des aspects observationnels. Cette partie s'abstient de tout aspect faisant appel au formalisme mathematique. Ces ecoulements peuvent etre decrits, au moins partiellement, en resolvant les equations magnetohydrodynamiques, axisymetriques et stationnaires. Ce formalisme, a la base de la plupart des theories, est expose dans la Partie 2. Il permet d'introduire quantitativement les integrales premieres qu'un tel systeme possede. Ces dernieres sont amenees a jouer un role important dans la comprehension des phenomenes d'acceleration ou de collimation, en particulier le taux de perte de masse, le taux de perte de moment angulaire ou l'energie du rotateur magnetique. La difficulte de modelisation reside dans l'existence de points critiques, propres aux equations non lineaires, qu'il faut franchir. La nature physique et la localisation de ces points critiques fait l'objet d'un debat important car ils sont la clef de voute de la resolution. Nous introduisons donc la notion de topologie des points critiques (Parties 3 et 4) en allant du cas le plus simple, hydrodynamique a symetrie spherique, aux cas plus complexes, magnetohydrodynamiques et axisymetriques. Une attention particuliere est donnee aux modeles auto-similaires qui, par leur approche semi-analytique, permettent de degager des idees simples sur le probleme. A la lumiere de ces notions, nous pouvons confronter plus quantitativement que dans la Partie 1, les resultats obtenus par les differents modeles sur la morphologie des ecoulements. Nous montrons ainsi que la collimation magnetique des vents en jets est un phenomene largement attendu d'un point de vue theorique. Cependant, si la collimation peut etre conique, parabolique ou cylindrique (Partie 4), c'est la collimation cylindrique qui semble la configuration la plus favorable. La forme de la collimation peut etre alors utilisee comme outil de prediction sur les conditions physiques dans l'ecoulement et a sa source.
Stochastic simulation of quantum dissipative dynamics

As a system can be separated from its heat bath via a decoupling scheme based on the Hubbard-Stratonovich transformation, the quantum dissipative dynamics is exactly described by the average of the random system moving in the stochastic field induced by the bath. As a test of this stochastic formalism, a direct numerical implementation is employed to simulate the spontaneous decay of a two-state atom. In contrast, the validity of a deterministic algorithm based on the stochastic scheme is investigated. Moreover, a mixed random-deterministic approach is established and its efficiency is exemplified by studying the exact dynamics for the spin-boson model at zero temperature.
Covariance Intersection Fusion Kalman Estimator for Multi-Sensor System with Measurements Delays

To handle the state estimation fusion problem between local estimation errors for the system with unknown cross-covariances and to avoid a large computation complexity of cross-covariances, for a multi-sensor linear discrete time-invariant stochastic system with time-delayed measurements, by the measurement transformation method, an equivalent system without measurement delays is obtained, and then using the covariance intersection (CI) fusion method, the covariance intersection fusion steady-state Kalman estimator is presented. It is proved that its accuracy is higher than that of each local estimator, and is lower than that of optimal Kalman fuser weighted by matrices with known cross-covariances. A Monte-Carlo simulation example shows the above accuracy relations, hence it has good performances.
Multiple Imputation of Industry and Occupation Codes in Census Public-use Samples Using Bayesian Logistic Regression

Abstract We describe methods used to create a new Census data base that can be used to study comparability of industry and occupation classification systems. This project represents the most extensive application of multiple imputation to date, and the modeling effort was considerable as well—hundreds of logistic regressions were estimated. One goal of this article is to summarize the strategies used in the project so that researchers can better understand how the new data bases were created. Another goal is to show how modifications of maximum likelihood methods were made for the modeling and imputation phases of the project. To multiply-impute 1980 census-comparable codes for industries and occupations in two 1970 census public-use samples, logistic regression models were estimated with flattening constants. For many of the regression models considered, the data were too sparse to support conventional maximum likelihood analysis, so some alternative had to be employed. These methods solve existence and .
Approximate Loop Transfer Recovery Method for Designing Fixed-Order Compensators

An approach is outlined for designing fixed-order dynamic compensators for multivariable time-invariant linear systems, based on minimizing a linear quadratic performance index. The formulation is done in an output feedback setting that exploits an observer canonical form to represent the compensator dynamics. The formulation also precludes the use of direct feedback of the plant output. The main contribution lies in defining a method for penalizing the states of the plant and of the compensator, and for choosing the distribution on initial conditions so that the loop transfer matrix approximates that of a full-state feedback design. When linear quadratic regulator theory is used to do the full-state feedback design, the approach can result in good gain and phase margin characteristics. Two examples are given to illustrate the effectiveness of the approach. The first treats the problem of pointing a flexible structure, and the second is a helicopter flight control problem using a tenth-order model for the fuselage and rotor dynamics. Both of the examples considered in this paper are for nonsquare plants.
The bivariate diameter–magnitude function of galaxies in the ESO-LV catalogue

We investigate the joint distribution of magnitudes and diameters of galaxies, the bivariate diameter-magnitude distribution function, using parametric and non-parametric maximum-likelihood methods. A diameter- and magnitude-limited sample is extracted from the ESO-LV catalogue and is fitted by a bivariate function of the form[GRAPHICS]where D and M are metric diameters and absolute magnitudes within the 25 mag arcsec-2 blue isophote. The maximum-likelihood estimates of the parameters of the bivariate function for a sample consisting of 529 galaxies of all morphological types are D* = 2260 +/- 97 km s-1 arcmin, A = - 4.85 +/- 0.12, B = - 0.34 +/- 0.44 and sigma(M) = 0.668 +/- 0.024. We compare the diameter and luminosity functions derived from the bivariate function with earlier studies.
Resonant inelastic hard x-ray scattering with diced analyzer crystals and position-sensitive detectors

A novel design of a high-resolution spectrometer is proposed for emission spectroscopy and resonant inelastic hard x-ray scattering applications. The spectrometer is based on a Rowland circle geometry with a diced analyzer crystal and a position-sensitive detector. The individual flat crystallites of the diced analyzer introduce a well-defined linear position-energy relationship within the analyzer focus. This effect can be exploited to measure emission spectra with an unprecedented resolution. For demonstration, a spectrometer was constructed using a diced Si(553) analyzer working at the CuK edge with an intrinsic resolution of 60meV. With the proposed design, spectrometers operating at the K edges of 3d transition metals can have intrinsic resolutions below 100meV even with analyzer crystals not working in Bragg-backscattering conditions.
Modelling of block-scale macrodispersion as a random function

Numerical modelling of solute dispersion in natural heterogeneous porous media is facing several challenges. Amongst these we highlight the challenge of accounting for high-frequency variability that is filtered out by homogenization at the subgrid scale and the uncertainty in the dispersive flux for transport under non-ergodic conditions. These two effects when combined lead to inaccurate representation of the dispersive fluxes. We propose to compensate for this deficiency by defining a block-scale dispersion tensor and modelling it as a random space function ℳij. The derived dispersion tensor is a function of several length scales and time. Grid blocks will be assigned dispersion coefficients generated from the ℳij distribution. We will show the dependence of ℳij on the spatial variability of the conductivity field, on the contaminant source size, on the travel time and on the grid-block scale. For an ergodic source, a statistically uniform conductivity field and very large grid blocks, ℳij is equal to the macrodispersion coefficients proposed by Dagan (J. Fluid Mech., vol. 145, 1984, p. 151) with zero variance. For an ergodic source and non-uniform conductivity field with a finite-size grid block, ℳij approaches the model proposed by Rubin et al. (J. Fluid Mech., vol. 395, 1999, p. 161). In both cases, ℳij is defined by its mean value with zero variance. ℳij is subject to uncertainty when the source is non-ergodic and when the grid block is defined by a finite scale. When the grid-block scale approaches zero, which means that the spatial variability is captured completely on the numerical grid, ℳij approaches zero with zero variance. In addition, we provide a complete statistical characterization of ℳij by invoking the concept of minimum relative entropy, thus providing upper bounds on the uncertainty associated with ℳij.
NIR image reconstruction using a single-rotating-source/detector scanning device

The research aims at developing an NIR tomography system using a single rotating source/detector scanning device associated with an image reconstruction scheme. Several simulation results concerning the phantom with one, two or three targets are presented. Additionally, the developed system is validated by a hemoglobin phantom inserted by another different volume density one.
Quaternion‐based rigid body rotation integration algorithms for use in particle methods

The resolution of translational motion in discrete element method and molecular dynamics applications is a straightforward task; however, resolving rotational motion is less obvious. Many applications update rotation using an explicit integration involving products of matrices, which has well‐known drawbacks. Although rigid body rotation has received attention in large‐angle rotation applications, relatively little attention has been dedicated to the unique requirements of particle methods using explicit time‐stepping algorithms. This paper reviews existing explicit algorithms and shows the benefits of using a quaternion‐based re‐parameterization of both the central difference algorithm and the approach of Munjiza et al. (Int. J. Numer. Meth. Engng 2003; 56:36–55). The improvement not only provides guaranteed orthonormality of the resulting rotation but also allows the assumption of small‐angle rotation to be relaxed and the use of a more accurate Taylor expansion instead. The current and quaternion‐based algorithms are compared for accuracy and computational efficiency. Copyright © 2007 John Wiley & Sons, Ltd.
A simple method, the -history method, of determining the heat of fusion, specific heat and thermal conductivity of phase-change materials

A simple method of determining the melting point, heat of fusion, specific heat and thermal conductivity of phase-change materials (PCMs) is presented. Compared with other methods, such as conventional calorimetric methods, differential thermal analysis and differential scanning calorimetry methods, it has the following salient features: the experimental unit is simple, able to measure the heat of fusion, specific heat and thermal conductivity of several samples of PCMs simultaneously and allows one to observe the phase-change process of each PCM sample. Using the method, the thermophysical properties of various salt hydrates, paraffin and some PCMs developed by us were measured. For the PCMs whose thermophysical properties are available in the literature, our results gave fairly good agreement. The method is especially useful for the selection of lots of candidate PCMs used for the purpose of engineering and for preparing new PCMs.
Optical modeling of thin-film silicon solar cells by combination of the transfer-matrix method and the raytracer algorithm

We discuss an optical model which describes silicon thin-film solar cells with rough interfaces in a fast and easy way. In order to simulate thin layer stacks with rough interfaces diffuse scattering as well as interference effects have to be taken into account. Algorithms like the finite-difference time-domain method (FDTD) solve the Maxwell Equations, and therefore fulfil these demands; yet, they take a considerable amount of simulation time and computation capacity. To overcome these drawbacks, an optical model was developed which combines the transfer-matrix method (TMM) and the raytracer algorithm. The fraction of TMM and raytracer in the model is determined by a separating function which can be interpreted as the integral haze. In order to verify the combined optical model, a series of amorphous silicon single cells with varying intrinsic layer thicknesses was produced on two different kinds of textured substrates. The results of the combined optical model are compared to measured data and the simulation results of the FDTD method. We show that the combined optical model yields good results at low simulation time.
Maxima for Graphs and a New Proof of a Theorem of Turán

Maximum of a square-free quadratic form on a simplex. The following question was suggested by a problem of J. E. MacDonald Jr. (1): Given a graph G with vertices 1, 2, . , n. Let S be the simplex in En given by xi ≥ 0, Σxi = 1. What is
Switchable phononic wave filtering, guiding, harvesting, and actuating in polarization-patterned piezoelectric solids

We demonstrate the ability to manipulate the propagation of phononic (elastic, acoustic) waves in two-dimensional piezoelectric solids by spatially patterning the polarization distribution. We simulate the wave fields by the finite element method and demonstrate the ability to dynamically alter the wave propagation by switching (on/off) the piezoelectric behavior by operating the electrodes in a closed or open circuit configuration. The piezoelectric polarization patterns are nonintuitive and are determined by topology optimization. We illustrate the interesting response of optimally patterned phononic devices with four examples: a filter, a waveguide, an energy harvester, and a wave actuator.
Impacts of the High-Resolution Sea Surface Temperature Distribution on Modeled Snowfall Formation over the Yellow Sea during a Cold-Air Outbreak

AbstractHigh-resolution sea surface temperature (SST) products and idealized SST distributions were used to simulate snowfall over the Yellow Sea during 30–31 December 2007 using the Weather Research and Forecasting Model (WRF). Large differences were found between the SST distributions in the New Generation Sea Surface Temperature (NGSST) and Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA) datasets near the Yellow Sea coast. Idealized SST datasets were defined to examine the influence of this difference in detail. The SST differences influenced the cloud streets and resultant snowfall formation. In simulations with the idealized SST distributions, convection developed and intensified later when the SST gradient was increased. In addition, the intensity of cloud streets was enhanced along the center of the flow. The simulations using the NGSST dataset showed widely distributed cloud streets and snowfall and heavier snowfall over the western Korean Peninsula, while those using the OSTIA da.
The neutral hydrogen deficiency of the cluster A262

Seventy-two galaxies in the spiral-rich cluster A262 have been observed in the 21 cm line at Arecibo of which 67 have been observed by us. The H I content of individual galaxies, as compared with that of a sample of isolated galaxies, depends on the distance from the core of the cluster; while pronounced H I deficiency is observed near the central parts, normal amounts of H I are observed in the cluster periphery. With the newly available redshifts, a revised set of dynamical parameters for the cluster are given.
Synthetic Spectra and Mass Determination of the Brown Dwarf Gliese 229B

We present preliminary nongray model atmospheres and interiors for cool brown dwarfs. The resulting synthetic spectra are compared to available spectroscopic and photometric observations of the coolest brown dwarf yet discovered, Gl 229B (Nakajima et al.). Despite the grainless nature of the present models, we find that the resulting synthetic spectra provide an excellent fit to most of the spectral features of the brown dwarf. We confirm the presence of methane absorption and the substellar nature of Gl 229B. These preliminary models set an upper limit for the effective temperature of 1000 K. We also compute the evolution of brown dwarfs with solar composition and masses from 0.02 to 0.065 M☉. While uncertainties in the age of the system yield some indeterminateness for the mass of Gl 229B, the most likely solution is m ≈ 0.04-0.055 M☉. In any case, we can set an upper limit m = 0.065 M☉ for a very unlikely age, t = 10 Gyr.
Basic plasma physics experiments and modeling of space phenomena on a large inductively coupled magnetoplasma device

Large KROT device is developed for modeling of space plasma physics phenomena and studies of interaction of super‐strong electromagnetic radiation with plasmas. The core of the facility is pulsed RF plasma source with MW power level. Well repeated and highly uniform plasma, magnetized or not, can be produced in a volume of several tens of cubic meters. An overview of the facility operational parameters is presented along with the results of recent experiments.
Measurement of small angular displacement by a modified moire technique

Small angle measurement using a modified moire interference technique is reported. The range of angle measurement for 25-μm pitch gratings is about ± 25 μrad and the accuracy of measurement is of the order of 0.2 μrad with a time constant of 0.1 s. A piezoelectric transducer (PZT) is used for angular displacement. The angular sensitivity under the present experimental conditions is found to be of the order of 21.8 mV/μrad.
Empirical Bayes Approach to Improve Wavelet Thresholding for Image Noise Reduction

Wavelet threshold algorithms replace small magnitude wavelet coefficients with zero and keep or shrink the other coefficients. This is basically a local procedure, because wavelet coefficients characterize the local regularity of a function. Although a wavelet transform has decorrelating properties, structures in images, like edges, are never decorrelated completely, and these structures appear in the wavelet coefficients: a classification based on a local criterion-like coefficient magnitude is not the perfect method to distinguish important, uncorrupted coefficients from coefficients dominated by noise. We therefore introduce a geometrical prior model for configurations of important wavelet coefficients and combine this with local characterization of a classical threshold procedure into a Bayesian framework. The local characterization is incorporated into the conditional model, whereas the prior model describes only configurations, not coefficient values. More precisely, local characterization favors configurations with clusters of important coefficients. In this way, we can compute, for each coefficient, the posterior probability of being “sufficiently clean. ” This article proposes and motivates the particular and original choice of the conditional model. Instead of introducing this Bayesian framework, we could also apply heuristic image processing techniques to find clustered configurations of large coefficients. This article also explains the benefits of the Bayesian approach compared to these simple techniques. The parameter of the prior model is estimated on an empirical basis using a pseudolikelihood criterion.