Miracle-dz/UniFAR-FTUs huggingface dataset:
Fluid Structure Interaction Modelling for the Vibration of Tube Bundles: Part II—Homogenization Method Based on the Navier Stokes Equations

It is well known that a fluid may strongly influence the dynamic behaviour of a structure. Many different physical phenomena may take place, depending on the conditions: fluid at rest, fluid flow, little or high displacements of the structure. Inertial effects can take place, with lower vibration frequencies, dissipative effects also, with damping, instabilities due to the fluid flow (Fluid Induced Vibration). In this last case the structure is excited by the fluid. The paper deals with the vibration of tube bundles in a fluid, under a seismic excitation or an impact. In this case the structure moves under an external excitation, and the movement is influenced by the fluid. The main point in such system is that the geometry is complex, and could lead to very huge sizes for a numerical analysis. Many works has been made in the last years to develop homogenization methods for the dynamic behaviour of tube bundles. The size of the problem is reduced, and it is possible to make numerical simulations on wide tubes bundles with reasonable computer times. These homogenization methods are valid for “little displacements” of the structure (the tubes), in a fluid at rest. The fluid movement is governed by the linear Euler equations (without the convective term). In this case, only “inertial effects” will take place, with globally lower frequencies. It is well known that dissipative effects due to the fluid may take place, even if the displacements of the tube are no so high, or if the fluid is not still. Such effects may be described in the homogenized models by using a Rayleigh damping, but the basic assumption of the model remains the “perfect fluid” hypothesis. It seem necessary, in order to get a best description of the physical phenomena, to build a more general model, based on the general Navier Stokes equation for the fluid. The homogenization of such system will be much more complex than for the Euler equations. The paper presents the first step in the building of a method based on the homogenization of the Navier Stokes equations.Copyright © 2011 by ASME
Impacts of the Nile Delta land‐use on the local climate

This is a numerical study of the effects of the Nile Delta (ND) man‐made greening on local climate. We compared a control simulation, which employs the present‐day ND vegetation, with a desertification experiment. It was found that the low surface albedo of the agricultural ND increases net radiation, which in turn raises potential evapotranspiration (PET). This suggests that agricultural use increases the water demand by enhancing PET. Non‐local effects are also observed on a frontal system over the eastern Mediterranean Sea that shifted farther away from the coast. This shift is attributed to a stronger land breeze in the present‐day land‐cover. Copyright © 2012 Royal Meteorological Society
Polymer evaluation by using the thickness longitudinal and shear vibrations of piezoelectric ceramics : application to the monitoring of thermosetting resins' polymerization

This work deals with the analysis of the electric impedance of piezoelectric ceramics embedded in viscoelastic materials. By using a theoretical approach, we show that this parameter is a function of the viscoelastic properties of the medium surrounding the piezoelectric ceramic. Then a method for extracting the viscoelastic properties of the outside medium from the piezoelectric ceramic electric impedance is described. Finally, this technique is used for monitoring the polymerization of epoxy-amine resins.
A Discontinuous Phase-Space Finite Element Discretization of the Linear Boltzmann-Vlasov Equation for Charged Particle Transport

We examine the modeling of charged-particle transport when both collision processes with background media and electromagnetic effects are important using the Boltzmann-Vlasov equation. We derive and transform the Boltzmann-Vlasov equation into a form very similar to the standard linear Boltzmann equation with additional operators. We apply the discontinuous finite element methods for discretization in the spatial, energy, and angular variables. An implementation of these methods demonstrates correct transport behavior for fixed electric and magnetic fields. We also demonstrate coupling to Maxwell's equations with a simple electromagnetic solver to generate self-consistent fields.
Diluted magnetic semiconductor of p-type GaN epilayers implanted with Mn+ ions

The study of diluted magnetic semiconductor based on GaN was performed employing a variety of various measurement techniques. p-type GaN epilayers were prepared by metalorganic chemical vapor deposition and were subsequently implanted with Mn+ ions. The properties of Mn+ ion-implanted GaN epilayers were investigated with optical and magnetic measurements. The results of photoluminescence (PL) measurement show that optical transitions related to Mn apparently appear at 2.5 and around 3.0 eV. It is confirmed that the PL peak at 2.5 eV is a donor-Mn acceptor transition and the PL peak around 3.0 eV is a conduction band-Mn acceptor transition. Ferromagnetic hysteresis loop was observed, and the temperature dependent-magnetization displayed a ferromagnetic behavior persisting up to ∼270 K.The study of diluted magnetic semiconductor based on GaN was performed employing a variety of various measurement techniques. p-type GaN epilayers were prepared by metalorganic chemical vapor deposition and were subsequently implanted with Mn+ ions. The properties of Mn+ ion-implanted GaN epilayers were investigated with optical and magnetic measurements. The results of photoluminescence (PL) measurement show that optical transitions related to Mn apparently appear at 2.5 and around 3.0 eV. It is confirmed that the PL peak at 2.5 eV is a donor-Mn acceptor transition and the PL peak around 3.0 eV is a conduction band-Mn acceptor transition. Ferromagnetic hysteresis loop was observed, and the temperature dependent-magnetization displayed a ferromagnetic behavior persisting up to ∼270 K.
Parametric transducers for resonant bar gravitational wave antennae

A new lumped element model of a two-mode resonant bar antenna coupled to a parametric transducer is presented and verified experimentally. The capacitance-modulated cavity transducer is represented in scattering parameter form, and is augmented to include the observable amplitude- and phase-modulated components of the pump oscillator, which simplifies calculations of amplitude-modulated to phase-modulated and phase-modulated to amplitude-modulated conversions. This representation enables the definition of the amplitude-modulated and phase-modulated components of transducer electro-mechanical coupling. Theory is verified from experimental data from the detector at the University of Western Australia, which uses a superconducting re-entrant cavity transducer. Comparisons for a proposed high-Q sapphire transducer are presented and compared with the present re-entrant cavity transducer. This model allows us to optimize the transfer function of the UWA detector, minimizing the effect of seismic noise at a set electro-mechanical coupling.
Attitude control of space robot by arm motion

A path-planning method of a space robot manipulator arm is presented in this paper. The purpose of the path planning is to control the satellite's attitude by the arm's motion. The joint angles are expressed by two parameters and a relation between the attitude change and the motion of the parameters is derived. Based on this relation, an algorithm for the joint angle path to cause the desired attitude change is proposed. An attitude control measure is also introduced to show the difficulty of changing attitude by arm motion. Numerical studies are executed using a space robot model with a manipulator arm with six degrees of freedom. The result shows that there are some directions where the attitude change is easily achieved by the arm motion. The validity of the proposed algorithm is confirmed by numerical simulations.
Torque Control of a Rehabilitation Teaching Robot Using Magneto-Rheological Fluid Clutches

A new robot that makes use of MR-fluid clutches for simulating torque is proposed to provide an appropriate device for training physical therapy students in knee-joint rehabilitation. The feeling of torque provided by the robot is expected to correspond to the torque performance obtained by physical therapy experts in a clinical setting. The torque required for knee-joint rehabilitation, which is a function of the rotational angle and the rotational angular velocity of a knee movement, is modeled using a mechanical system composed of typical spring-mass-damper elements. The robot consists of two MR-fluid clutches, two induction motors, and a feedback control system. In the torque experiments, output torque is controlled using the spring and damper coefficients separately. The values of these coefficients are determined experimentally. The experimental results show that the robot would be suitable for training physical therapy students to experience similar torque feelings as needed in a clinical situation.
Synthesis and temperature dependent photoluminescence properties of Mn doped Ge nanowires

Ge nanowires were grown on Au-coated Si (100) substrates using vapor-liquid-solid technique. Temperature dependent photoluminescence spectra of Mn doped nanowires showed dominant impurity emissions due to transition from an intermediate T41 to A61 ground state of Mn2+ in Ge nanowire. Magnetic hysteresis loop showed paramagnetic to ferromagnetic transition with decreasing temperature. Temperature dependent electrical resistivity indicated the formation of Mn related acceptor level in Ge at 0.159 eV from the valence band.
Silicon nanocrystallites in buried SiOx layers via direct wafer bonding

A combination of SiO vapor-deposition and direct wafer bonding is used to produce buried layers of SiOx. By thermally induced decomposition, Si nanocrystals embedded in SiO2 are obtained. Decomposition of the silicon suboxide is observed by studying the Si-O-Si stretching vibration in the infrared range. This phase separation process is found to start already at 400 °C and to be mostly complete after 1 h at 800 °C. Annealing at 1000 °C yields well established Si nanocrystallites of considerable density with diameters about 4 nm buried in the interface layer between the bonded silicon wafers.
STURM–LIOUVILLE PROBLEMS WITH BOUNDARY CONDITIONS RATIONALLY DEPENDENT ON THE EIGENPARAMETER. I

We consider the Sturm–Liouville equation $$ -y''+qy=\lambda y\quad\text{on }[0,1], $$ subject to the boundary conditions $$ y(0)\cos\alpha=y'(0)\sin\alpha,\quad\alpha\in[0,\pi), $$ and $$\frac{y'}{y}(1)=a\lambda+b-\sum_{k=1}^N\frac{b_k}{\lambda-c_k}. $$ Topics treated include existence and asymptotics of eigenvalues, oscillation of eigenfunctions, and transformations between such problems. AMS 2000 Mathematics subject classification: Primary 34B24; 34L20
Performance of variability in provenances of Jatropha curcas

Objective: To characterize different provenances of Jatropha curcas L. , introduced and collected, through morphoagronomic indicators, in order to select those with the best performance. Materials and Methods: The study was conducted during one year (2019) in areas of the Pastures and Forages Research Station Indio Hatuey. The work was done with plant material from Paraguay, Ecuador and eastern Cuba. The different Jatropha curcas L. provenances were propagated by seeds. The indicators height, number of branches, stem diameter, quantity of racemes and their length, quantity and length of inflorescences, quantity of fruits and their sizes, were measured, among other variables. The data were processed through the principal component (PCA), cluster and correlation analyses. Results: Of the variability, 96,8 % was explained through four components. The fruit quantity, length and width, quantity of seeds and their sizes, as well as quantity of inflorescences and stem diameter were the indicators with which 55,6 % of the variability was explained in the first two components. Five groups were formed. The second was the one with the best performance in six of the evaluated indicators. Conclusions: There is variability for the evaluated morphoagronomic traits. The provenance Ecuador 2 was the one with the best performance in six of the evaluated indicators. It was followed by Paraguay 2 in four indicators, for which both were selected and turned out to be promising for their study in future breeding programs.
Directional Reflectance and Emissivity of an Opaque Surface

Concepts, terminology, and symbols are presented for specifying and relating directional variations in reflectance and emissivity of an opaque surface element. Their relationship to more familiar concepts, including those of perfectly diffuse and specular reflectance, is given, and they are applied to illustrative examples. It is shown that, when the usual reciprocity relationship holds, the reflectance for a ray incident on an opaque surface element is related by Kirchhoff's law to the emissivity of that element for a ray emitted along the same line in the opposite sense.
A hydraulic shear stress model for rapid, highly concentrated flow

A hydraulic shear stress model for a uniform, steady flow on a slope of a mixture of water and a granular material al high concentration is presented here. The model includes stresses generated by particle-particle interactions along with those generated by fluid-bed interaction. Some results from the kinetic theory for granular flow are introduced to modify Bagnold's model for dispersive stresses. The model was verified experimentally by means of an inclined channel where silica-sand, supplied by a hopper, mixes with a uniform, steady water flow. Channel slopes range from 19 to 23 degrees. An interesting finding was obtained in the experiments presented here: there is not a continuous increase in velocity with depth of flow as stated by Manning's formula for the whole range of concentrations. The hydraulic model is able to reproduce the shape of the velocity vs. How depth curve and gives some insight about the mechanical behavior of the flow.
Proton cyclotron echoes and spurs observed on Alouette II and ISIS II

Proton cyclotron echoes and spurs observed on the topside sounder ionograms on the Canadian Alouette and ISIS satellites are phenomena related to the proton cyclotron frequency. They appear on the ionograms at apparent ranges which lead to a frequency close to the proton cyclotron frequency; the frequency is calculated by taking the reciprocal of the time elapsed between the transmission of the sounder pulse and the reception of the signal at the satellite. Most proton cyclotron echoes and spurs occur at frequencies below the electron plasma frequency, ƒN; the echoes occur predominantly at frequencies slightly above the electron cyclotron frequency, ƒH, while the spurs occur predominantly when a harmonic of ƒH is near ƒN. Over 1000 ionograms exhibiting proton cyclotron echoes and/or spurs were examined and were classified depending on apparent range and shape of the echoes or spurs. The major classifications were echoes only, spurs only, and spur-echo combinations. The subclassifications include one new type of spur which occurs at frequencies above ƒN. The classifications also reveal the absence of echoes with apparent ranges less than those corresponding to the calculated proton gyroperiod in the vicinity of the satellite. These results are compared with theories for the generation mechanism for proton cyclotron echoes and spurs.
Precise Li abundances in metal-poor stars: depletion in the Spite plateau

Abstract We present Li abundances for 73 stars in the metallicity range −3.5 < [Fe/H] < −1.0 using improved IRFM temperatures (Casagrande et al. 2009) with precise E(B-V) values obtained mostly from interstellar NaI D lines, and high-quality equivalent widths (σEW ~ 3%). At all metallicities we uncover a fine-structure in the Li abundances of Spite plateau stars, which we trace to Li depletion that depends on both metallicity and mass. Models including atomic diffusion and turbulent mixing seem to reproduce the observed Li depletion assuming a primordial Li abundance ALi = 2.64 dex (MARCS models) or 2.72 (Kurucz overshooting models), in good agreement with current predictions (ALi = 2.72) from standard BBN.
Development of Multi-Wavelength-Range High-Resolution Spectrometer for Hydrogen Atomic and Molecular Emission Lines

wavelength ranges are 0.008, 0.009, 0.010, 0.008, and 0.007nm. We apply the spectrometer to the observation of emissions from a LHD plasma. The observed profiles of these emission lines and bands show polarization dependence. The absolute intensities of these emissions are also estimated. c
An Impact Source Localization on a Spherical Shell by Using Smoothed Wigner-Ville Distributions

A technique to localize an impact source for an elastic spherical shell is proposed. The conventional source localization techniques when the source is located on a dispersive medium, require both the time-of-arrival differences (TOADs) between the transducer signals and the group velocities. In practice, the material properties or the geometry of the medium are not fully informed, therefore the group velocity is not available. Furthermore, they are only applicable if we have a high signal-to-noise ratio (SNR). In this paper, we propose a method that can be applicable in practice, which does not need to know the group velocity, when we have a relatively small SNR. The scanning procedure over the structure to acquire a minimum variance point of the estimated group velocities is suggested. To reduce the noise effect, an exponential function is asymmetrically weighted in smoothed Wigner-Ville distributions (WVDs). Experiments have been conducted to confirm the validity of this method. As a result, the proposed technique is found to be effective for an impact source localization for a spherical shell without prior information on the group velocity, even in a noisy environment.
Degradation and failure of carbon nanotube field emitters

The failure of individual multiwall carbon nanotubes during field emission and two-probe characterization was studied in a scanning electron microscope on emitters grown by chemical vapor deposition. The failures induced by high currents during two-probe measurements led to a sundering of the tube in or near its middle, which is consistent with a local evaporation due to resistive heating. Conversely, failures during field emission occurred at or near the substrate-emitter contact. We show that the degradation is due to mechanical failure of the contact at low applied fields, and to resistive heating (probably enhanced by the mechanical stress) at high emitted currents.
A two-micron Galactic survey

The first results are presented here of the Two-Micron Galactic Survey (TMGS). The TMGS is the most sensitive near-infrared survey of the Galactic plane yet attempted on a large scale. The Galactic plane has been drift-scanned in several regions over the areas −5° < l < 30°, |b| ≤ 15° and 30° < l < 180°, |b| ≤ 5°. The discussion in this paper concentrates mainly on three extensively mapped areas centred on δ = −1°, −23° and −30°, covering a total of 138 deg 2 of sky. The survey is complete in the areas covered to magnitude m K ≃ + 9.8 mag. So far, a total area of 255 deg 2 has been mapped and 470 000 objects have been detected, the majority of these in the Galactic plane and with no known visible counterparts
On Kepler Ellipses Starting from a Point in Space

The one-parameter family of Kepler ellipses is considered, which originates when mass points are released with the same initial velocity but in all directions at a point which has a finite distance from the attractive center. It is found that (a) the locus of the second foci is a circle whose center is the point of release, (b) the directrices of the ellipses have as envelope a conic which can be an ellipse or a hyperbola, (c) the envelope of the orbital ellipses is itself an ellipse, whose two foci are the attractive center and the point of release, and (d) that, if the particles are released at the same instant, they will return to the point of release simultaneously.
Attention Electroencephalogram Analysis Based on Jensen-Shannon Divergence Analysis

In this paper, the complexity analysis method based on Jensen-Shannon Divergence was used to calculate the complexity of the Idle states, the close eyes states and the count numbers states electroencephalogram. The study found that the JSD value of close eyes states EEG was highest, followed by that of the Idle states EEG, and that of the count numbers states EEG was minimum. The result can be used to assisted clinical diagnosis.
Ground-state Ps formation in e+-H2 scattering using the FBA

Ground-state capture cross sections in e+-H2 scattering are calculated in the energy region 10-1000 eV using the first Born approximation. The approximation employed by Sural and Mukherjee (1970) in predicting the first Born capture cross section is found to be unjustified. Present capture cross sections for incident positron energies E>or=30 eV are in good agreement with the measured data.
Synthesis of English monosyllables by demisyllable concatenation

The use of demisyllables plus voice‐assimilated phonetic affixes (/− s, − z, − t/, etc.), rather than segments or syllables, as the basic units in speech synthesis would have important advantages [O. Fujimura, J. Acoust. Soc. Am. 59, S55(A) (1976)]. We have tested the practicality of such a model for monosyllabic words of English, using an inventory of demisyllables with a variety of nonaffixed clusters and syllable nuclei. Each initial demisyllable is prepared so as to include a constant length of the transitional portion, and nucleus length variations dependent on the final consonant(s) are automatically included in the “vowel” portion of the final demisyllable. Syllable nucleus “coloration” by postvocalic nasals, /r/, or /l/ is also found to be automatically accounted for in this scheme. For example, the initial demisyllable excised from CVC may be joined with − VN to make a natural‐sounding CVN syllable. These experiments used both a parallel‐type formant analyzer—synthesizer [J.P. Olive and M.J. Macchi, J. Acoust. Soc. Am. 58, S23(A) (1975)] and an LPC processor, with some retouching, and with minimal smoothing across the concatenative boundary of the parameters.
Multiwalled carbon nanotube/polydimethylsiloxane composite films as high performance flexible electric heating elements

High performance elastomeric electric heating elements were prepared by incorporating various contents of pristine multiwalled carbon nanotube (MWCNT) in polydimethylsiloxane (PDMS) matrix by using an efficient solution-casting and curing technique. The pristine MWCNTs were identified to be uniformly dispersed in the PDMS matrix and the electrical percolation of MWCNTs was evaluated to be at ∼0.27 wt. %, where the electrical resistivity of the MWCNT/PDMS composite films dropped remarkably. Accordingly, the composite films with higher MWCNT contents above 0.3 wt. % exhibit excellent electric heating performance in terms of temperature response rapidity and electric energy efficiency at constant applied voltages. In addition, the composite films, which were thermally stable up to 250 °C, showed excellent heating-cooling cyclic performance, which was associated with operational stability in actual electric heating applications.