Miracle-dz/UniFAR-FTUs huggingface dataset:
Measurements of sound propagation in narrow tubes

The propagation of sound in hollow tubes is a fundamental theme common to many areas of classical acoustics. Kirchhoff's theory explaining the propagation of sound in a circular tube is now playing an important role as a starting point in studying sound in porous media. This paper reports on measurements of the phase velocity and attenuation coefficient in the narrow regions of tubes, where the sound undergoes anomalous dispersion and is seen to slow down remarkably to the extent that a runner can pass ahead of it. Kirchhoff's theory can be verified by experiment over a wide range of thermodynamical conditions, from isentropic to isothermal.
Finite element toolbox for generic coupling (magnetic, thermal, etc.)

Software already allows one to carry out multiple coupling, however, they are often destined to only one type of coupling and it can prove difficult to integrate a new physical field. We have developed an adapted finite element toolbox for generic coupling. Thanks to an object oriented approach, it is possible to carry out multiple coupling. It is easy to add a new coupling transparently with a minimum of development. With the choice of an indirect coupling method, one can integrate specific solution methods, independently developed. We present the implementation in SIC (Systeme Interactif de Conception) software, one of the first finite element software using an object approach. We have chosen it for its FORTRAN object manager and the various physical models included. We have validated all our developments on the physical process of induction heating.
Calibration of a shortwave reference standard by transfer from a blackbody standard using a cryogenic active cavity radiometer

The Clouds and the Earth's Radiant Energy System (CERES) instruments for the NASA Earth Observing System each contain three broadband scanning radiometers operating in bands at wavelengths from 0.3 to 5 /spl mu/m, 8 to 12 /spl mu/m and 0.3 to >150 /spl mu/m. The primary radiance standard for CERES ground calibration is an absolute blackbody. This standard provides radiance calibration in the long wave spectral region over a blackbody temperature range of 200 K to 320 K. A cryogenic active cavity radiometer operating at liquid helium temperature is used to transfer the radiance scale of the blackbody to a secondary, shortwave calibration source. The longwave to shortwave calibration transfer makes use of the spectrally flat absorptance of the ACR across the entire spectral region. The thermal properties of the copper receiver cavity at 4 K permit a noise equivalent power performance adequate for calibration of the shortwave reference source in a series of narrow (10% wide) spectral bands which span the shortwave spectral region. The narrow spectral regions greatly reduce the errors in the relative spectral response knowledge of the shortwave source. Results are presented for a transfer that was made during validation tests of the ground calibration system in preparation for the CERES Functional Test Model instrument calibration. <<ETX>>
An efficient plane wave spectral analysis to predict the focal region fields of parabolic reflector antennas for small and wide angle scanning

An efficient approach is described for calculating the field distribution in the focal region of an electrically large, symmetric or offset parabolic reflector antenna with an arbitrary rim contour, when the concave reflector surface is fully illuminated by an obliquely incident arbitrary electromagnetic plane wave. The dominant contribution to the focal-region fields is found by transforming the physical-optics integral over the reflector surface into a plane-wave spectral (PWS) integral. The PWS integral is evaluated rapidly via the fast Fourier transform (FET) algorithm to furnish, in only a single computation, the field for every place in the focal plane (or any plane parallel to it) within the focal region for a given direction of the incident wave. The correction to the physical-optics field is relatively small in the focal region and may therefore be neglected. Numerical results based on this PWS approach are presented, and their accuracy is established by comparison with results based on other approaches. >
Characterisation of new Leonov parameters for PET

The implementation of a new version of the Leonov model was done by Lambert van Breemen. The used implementation is one of the earlier versions of the new approach, from October 2004. This implementation uses some different parameters for describing softening and incorporating thermo-mechanical history of a material. These parameters are D0 instead of the earlier used D∞ and the parameters for the softening function: s0, s1 and s2. These new parameters are determined with the use of indentation tests and compression tests. Also some problems encountered with the use of MSC. MARC for the indentation simulations are described. Some problems found where the instability of the Leonov model when dealing with distorted elements and the use of the internal MSC. MARC remeshing procedures.
Robust stability of two-dimensional uncertain discrete systems

We deal with the robust stability problem for linear two-dimensional (2-D) discrete time-invariant systems described by a 2-D local state-space (LSS) Fornasini-Marchesini (1989) second model. The class of systems under investigation involves parameter uncertainties that are assumed to be norm-bounded. We first focus on deriving the sufficient conditions under which the uncertain 2-D systems keep robustly asymptotically stable for all admissible parameter uncertainties. It is shown that the problem addressed can be recast to a convex optimization one characterized by linear matrix inequalities (LMIs), and therefore a numerically attractive LMI approach can be exploited to test the robust stability of the uncertain discrete-time 2-D systems. We further apply the obtained results to study the robust stability of perturbed 2-D digital filters with overflow nonlinearities.
Strongly coupled overdamped pendulums

It is shown, by a first-order perturbation expansion, that the dimensionality of the dynamical equations for the angular variables of two strongly coupled identical overdamped pendulums can be reduced from two to one. The resulting dynamical equation is seen to be similar to the one of a single pendulum with an additional fictitious torque characterized by a second harmonic contribution.
Demonstration of the CDMS II ZIP technology at a shallow underground site

The most recent CDMS data run (Run 20) was the first run in which multiple ZIP detectors were deployed. Three Si (0.100 kg each) and 3 Ge (0.250 kg each) ZIPs were run with the goals of fully testing such a configuration as well as measuring the γ, β, and n rates simultaneously with Ge and Si detectors. Calibration with γ and n sources established the bulk electron recoil leakage into the neutron band to be less than 0.2%. Low background data taken during the summer of 2000 produced a simultaneous measurement of the muon coincident neutron background with Si and Ge detectors.
The collapse time of a closed cavity

The collapse time of a closed cavity that is initially at rest in an incompressible, inviscid fluid of density ρ and ambient pressure p∞ has the form \[ t_1 = \{\rho/(p_{\infty} - p_c)\}^{\frac{1}{2}}\ell, \] where pc is the internal pressure, which is assumed to remain constant during collapse, and [ell ] is a length that depends only on the geometry of the cavity. A variational formulation of the dynamical problem is constructed from Jacobi's statement of the principle of least action. A single-degree-of-freedom approximation is developed from the similarity hypothesis that the cavity collapses through a family of similar surfaces with volume as the generalized co-ordinate. Two-degree-of-freedom approximations are given for both prolate and oblate spheroidal cavities and are used to obtain error estimates for the similarity approximation (approximately 2% for the limiting case of a needle-like, prolate spheroid and approximately ½ % for a disk-like, oblate spheroid). A perturbation analysis is developed for an approximately spherical cavity, which is found to have the same collapse time as a spherical cavity of equal volume within a factor 1 + O(e4), where e is a representative eccentricity. A first-order correction for surface tension is obtained.
Interaction of synthetic jet propulsion with airfoil aerodynamics at low Reynolds numbers

The use of synthetic jets for propulsion of fixed-wing Micro Air Vehicles (MAVs) is investigated experimentally in the low Reynolds number range. Interaction of a synthetic jet located at the trailing-edge of the wing with wing aerodynamics is studied with flow visualization and velocity measurements at low Reynolds numbers. The effects of excitation frequency, momentum coefficient, angle of attack, and Reynolds number were studied in detail. The separated region in the wake becomes smaller as the momentum coefficient is increased gradually. Once the momentum coefficient reaches a critical value, there is zero net drag. There is also reattachment of the separated shear layer near the trailing-edge, with expected enhancement in lift. Above the critical value of the momentum coefficient, the jet produces net thrust. Even at relatively higher incidences, zero net drag can be obtained and the reattachment of the shear layer to the upper wing surface is possible. The reattachment of the separated shear layer becomes easier with increasing Reynolds number. The favorable effect of increasing Reynolds number is most apparent at low Reynolds numbers. There is a strong effect of pulsing frequency and the results suggest an optimum range of Strouhal number St = 2 to 5. Also, preliminary experiments for a generic airfoil with internal actuator were carried out. Although the drag of this design is somewhat larger, zero net drag can be achieved when the synthetic jet is activated.
Running of Neutrino Parameters in Extra Dimensions

In recent years, extra-dimensional models have received new attention as possible extensions to the Standard Model (SM). In this thesis, we study a six-dimensional model with universal extra dimensions (UEDs). The extra dimensions are compactified, and all fields in the SM can probe them. From our four-dimensional point of view, we perceive them as towers of heavy particles, corresponding to the SM fields. In this thesis, we discuss the six-dimensional UED model together with an effective neutrino mass operator. We determine the renormalization group equations (RGEs) relevant to determine the renormalization group running of neutrino parameters. The RGEs are solved numerically and we thus determine the energy-dependence of the lepton mixing angles, the neutrino masses, and the gauge couplings in this model. We find that the mixing angle θ12, the neutrino masses and the gauge couplings exhibit significant running. The running has a power-law dependence, as it is boosted by contributions from the extra dimensions. The model is of particular interest, since it gives predictions at energies obtained in the Large Hadron Collider (LHC). The experiment have already provided restrictions of the size on the extra dimensions, and will hopefully enlighten us further regarding their existence.
Stochastic leadtimes in continuous‐time inventory models

This paper shows that one of the fundamental results of inventory theory is valid under conditions much broader than those treated previously. The result characterizes the distributions of inventory level and inventory position in the standard, continuous‐time model with backorders, and leads to the relatively easy calculation of key performance measures. We treat both fixed and random leadtimes, and we examine both stationary and limiting distributions under different assumptions. We consider demand processes described by several general classes of compound‐counting processes and a variety of order policies. For the stochastic‐leadtime case we provide the first explicit proof of the result, assuming the leadtimes are generated according to a specific, but plausible, scenario.
Point Targeting of Multisatellites via a Virtual Structure Formation Flight Scheme

This paper proposes a formation flight control scheme for spacecraft based on the virtual structure approach. The virtual structure approach treats the entire formation as a virtual rigid-body structure. With this approach, the geometric relationship among the spacecraft can be maintained during a maneuver. The information on the geometric relationships is used to complete the formation flight mission. Using rotational kinematics and rigid-body dynamics, the virtual structure formation algorithm calculates the reference position and attitude command to perform the synchronized maneuvers required to point to the desired target. The adaptive sliding mode control law is adopted to make the system track the reference command generated by the formation algorithm. An adaptive sliding mode controller, which combines the merits of the adaptive control scheme and the sliding mode control scheme, is proposed and used to make the spacecraft follow the specified position and attitude command. The stability of the proposed controller is analyzed by using the Lyapunov stability theorem, and a numerical simulation is performed to verify the effectiveness of the proposed formation algorithm and the adaptive sliding mode controller.
Remotal Sets in Orlicz Spaces

Let X be a Banach space, (I, μ) be a finite measure space. By L Φ(I, X), let us denote the space of all X-valued Bochner Orlicz integrable functions on the unit interval I equipped with the Luxemburg norm. A closed bounded subset G of X is called remotal if for any x ∈ X, there exists g ∈ G such that ‖x − g‖ = ρ(x, G) = sup {‖x − y‖: y ∈ G}. In this article, we show that for a separable remotal set G ⊂ X, the set of Bochner integrable functions, L Φ(I, G) is remotal in L Φ(I, X). Some other results are presented.
Numerical study of transient flow within a horizontal cylinder heated from below and cooled from the top

The time dependent natural convection in a horizontal circular cylinder, heated from below and cooled from above, is computed using the stream function-vorticity formulation for the two-dimensional equations of motion and energy. The fluid studied has a Prandtl number of 7. The range of Rayleigh numbers (Ra) presented in this paper is 580 ≤ Ra ≤ 100,000. For the range of Ra presented, the initial motion consists of four cells. As Ra is increased, a large single cell with two weak cells is formed. At low Rayleigh numbers, steady state solutions are obtained. At higher values of Ra, the flow becomes unsteady. The temperature, streamlines, relative total Kinetic Energy (KE) and Nusselt number are presented as functions of time.
Immersed boundary method for unsteady kinetic model equations

Predicting unsteady flows and aerodynamic forces for large displacement motion of microstructures requires transient solution of Boltzmann equation with moving boundaries. For the inclusion of moving complex boundaries for these problems, three immersed boundary method flux formulations (interpolation, relaxation, and interrelaxation) are presented. These formulations are implemented in a 2‐D finite volume method solver for ellipsoidal‐statistical (ES)‐Bhatnagar‐Gross‐Krook (BGK) equations using unstructured meshes. For the verification, a transient analytical solution for free molecular 1‐D flow is derived, and results are compared with the immersed boundary (IB)‐ES‐BGK methods. In 2‐D, methods are verified with the conformal, non‐moving finite volume method, and it is shown that the interrelaxation flux formulation gives an error less than the interpolation and relaxation methods for a given mesh size. Furthermore, formulations applied to a thermally induced flow for a heated beam near a cold substrate show that interrelaxation formulation gives more accurate solution in terms of heat flux. As a 2‐D unsteady application, IB/ES‐BGK methods are used to determine flow properties and damping forces for impulsive motion of microbeam due to high inertial forces. IB/ES‐BGK methods are compared with Navier–Stokes solution at low Knudsen numbers, and it is shown that velocity slip in the transitional rarefied regime reduces the unsteady damping force. Copyright © 2015 John Wiley & Sons, Ltd.
Decoupling and arbitrary pole placement in linear systems using output feedback

Linear multivariable systems are considered which can be decoupled by state-variable feedback, but arbitrary pole placement and decoupling cannot be achieved simultaneously. These systems cannot be decoupled using output feedback. A compensator is presented which allows decoupling and arbitrary pole placement in the augmented system using output feedback.
The Relationship between Large-Scale Convective Rainfall and Cold Cloud over the Western Hemisphere during 1982-84

Abstract Estimates of areal- and time-averaged convective precipitation derived from geostationary satellite imagery using a simple thresholding technique are presented. The estimates are based on measurements of the monthly mean fraction of 2.5° × 2.5° areas covered by clouds whose equivalent blackbody temperature in infrared imagery is below 235 K. The transformation between fractional coverage and rainfall amount is based upon comparisons of fractional coverages using a variety of temperature thresholds and spatial and temporal averaging scales with areal averaged rainfall from the GARP Atlantic Tropical Experiment. Three-year means of the estimated precipitation for the period December 1981-November 1984 are shown for each of the (3-month) calendar seasons and compared with published descriptions of the long-term seasonal mean rainfall fields. Over the tropical oceans agreement is quite good with no evidence of any systematic errors. Over the Americas, long-term means derived from station observations.
DSC‐SIP method for two‐dimensional scattering problem

A generalized high‐order finite‐difference method [discrete singular convolution‐symplectic integrator propagator (DSC‐SIP)] is proposed to analyze the electromagnetic scattering problem in which the time difference is discretized by the SIP and the spatial difference by the DSC.When compared with the standard finite‐difference time‐domain (FDTD) method, the DSC‐SIP method not only has higher stability and accuracy but also can save the computing memory space and CPU time with suitable meshes. Numerical examples are provided to show the high stability and effectiveness of the proposed method. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26104
The Number and Width of Classes in the Chi-Square Test

Abstract The Helmert transformation of a set of observations {xj }, j = 1, 2, …, N is applied to give a direct approach to the problem of boundary determination in the case of the χ2-test for location of the normal distribution, i.e. the choice of that set of boundaries which maximizes the power of the test. It is found that no significant increase in power can be achieved by taking a number of classes greater than 20; and even a number as small as 12 is sufficient. Moreover, a power of one-half is achieved for a number of classes much smaller than that required by the Mann-Wald approach. For a preassigned number of classes, symmetrically situated about the origin, it is found that the optimum partition corresponds to equal class-width of about 0.4 standard deviation with pooling of the terminal classes, and this is slightly more powerful than the equal class-probability partition.
Accelerations in isotropic and homogeneous turbulence and Taylor’s hypothesis

The validity of Taylor’s hypothesis is analyzed by comparing the root mean square (rms) values of full (Lagrangian) and inertial accelerations in an isotropic and homogeneous turbulent flow. Full, local, and inertial accelerations in turbulence were decomposed into solenoidal and potential components, which made it possible to avoid dealing, at least directly, with the pressure-gradient term in the Navier–Stokes equation. The evaluations of the correlation functions and spectra of the accelerations are presented. These evaluations have been obtained using the Batchelor [Proc. Cambridge Philos. Soc. 47, 359 (1951)] longitudinal structure function that describes statistical properties of the turbulent velocity field. This function is equally valid for both inertial and dissipative subranges. It was shown that the ratio of the rms values of the full and inertial accelerations depends on the Reynolds number Rλ only and decreases at large Rλ as Rλ−1/2. At Rλ of about 20 this ratio is close to 0.72. At Rλ of 10.
Radiometer and Profiler Analysis of the Effects of a Bore and a Solitary Wave on the Stability of the Nocturnal Boundary Layer

Abstract This study uses data from a microwave profiling radiometer (MPR), along with 915-MHz wind profiler, Doppler radar, and surface data to quantify the kinematic and thermodynamic effects of two wave features, an undular bore and a soliton, on the nocturnal boundary layer (NBL) at high temporal resolution. Both wave features passed directly over the MPR and the wind profiler, allowing for detailed analyses. The effects of the wave features on the convective environment are examined, and convective initiation (CI) associated with the wave features is discussed. The undular bore was illustrated well in Doppler velocity data, and profiler measurements indicated that it produced four wavelengths of upward and downward motion. MPR-derived time–height sections of potential temperature and mixing ratio showed an increase in the depth of the stable boundary layer, along with a decrease in stability, partially associated with mixing of the NBL. The soliton produced a temporary decrease in the depth of the NBL.
A new approach for the sliding mode control based on fuzzy reaching law

A scheme of the sliding mode control based on fuzzy reaching law for a class of nonlinear systems with uncertainties is proposed in this paper. Since the proper fuzzy logic control is applied to the reaching law, the quality is improved. At the same time, the chattering phenomenon is avoided. Simulation results show that the control system exhibits not only strong robustness and better quality control, but also avoiding the chattering phenomenon.
A comparison of absolute moment block truncation coding and the minimum mean square error quantizer

The Lagrange multiplier optimization technique is used to derive an exact relationship between absolute moment block truncation coding (AMBTC) and the minimum mean square error quantizer (MMSEQ). In addition, using computer simulation it is shown that the perceptual difference between the decoded images using these two approaches is almost unnoticeable. Furthermore, AMBTC and MMSEQ are separately incorporated into a subband coding scheme. The perceptual difference between the reconstructed images with subband coding is unnoticeable. While the MMSEQ requires an iterated search for the optimum threshold AMBTC uses the local mean value as the threshold. As a result, AMBTC is more practical than the MMSEQ. <<ETX>>