Value Of Scale Parameter Research Articles

On QCDQ 2-evolution of deuteron structure functionF 2 D (x D,Q 2) forx D>1

The deep-inelastic deuteron structure function (SF)F2D (xD,Q2) in the covariant approach in light-cone variables is considered. ThexD andQ2-dependences of SF are calculated. The QCD analysis of generated data both for non-cumulativexD 1 ranges is performed. It is shown that theQ2-evolution of SF is valid for ranges 0.275<xD<0.85 and 1.1<xD<1.4 for the same value of QCD scale parameter Λ. It is found that thexD-dependence of SF for the range is essentially different.

A NUMERICAL STUDY OF OSCILLATORY FLOW ABOUT A CIRCULAR CYLINDER FOR LOW VALUES OF BETA PARAMETER

A Hybrid Lagrangian/Eulerian Discrete Vortex Method has been used to simulate the flow around a circular cylinder in planar oscillatory flow at a value of the viscous scale parameter, β, of 76. A number of techniques are examined for estimating the forces acting on the cylinder. Surface pressure is calculated using the normal gradient of vorticity at the surface, by integrating the equation of motion along a radial line from the outer boundary of the mesh to the cylinder surface and by using Poisson’s equation. Predictions are compared with existing analytical results for low Keulegan Carpenter numbers and with recent measurements up to Keulegan Carpenter numbers of 30, made at a β of 70. These comparisons show that Wu's method, based on the generalized Blasius equation, gives accurate predictions and that surface pressure is predicted most accurately by using integration along a radial line. There is found to be good agreement between the computed and measured in-line forces across a range of KC values. Numerical flow field data is presented in the form of visualizations and, in order to be able to compare directly with visualization from experiments, passive markers are introduced into the computations. All the major vortex-shedding regimes observed in experiments at KC values up to around 30 are reproduced in the simulations.

A transform for multiscale image segmentation by integrated edge and region detection

Describes a transform to extract image regions at all geometric and photometric scales. It is argued that linear approaches have the shortcoming that they require a priori models of region shape. The proposed transform avoids this by letting the structure emerge, bottom-up, from interactions among pixels. The transform involves global computations on pairs of pixels followed by vector integration of the results. An attraction force field is computed over the image in which pixels belonging to the same region are mutually attracted and the region is characterized by a convergent flow. It is shown that the transform possesses properties that allow multiscale segmentation, or extraction of original, unblurred structure at all different geometric and photometric scales present. This is in contrast with much previous work wherein multiscale structure is viewed as the smoothed structure in a multiscale signal decimation. Scale is an integral parameter of the force computation, and the number and values of scale parameters associated with the image can be estimated automatically. Regions are detected at all a priori unknown scales resulting in automatic construction of a segmentation tree, in which each pixel is annotated with descriptions of all the regions it belongs to. Transform properties are presented for piecewise-constant images but hold for more general ones. Thus the proposed method is intended as a solution to the problem of multiscale, integrated edge and region detection, or low-level image segmentation. Experimental results are given.

Characterization of molecular shape resonances using different decouplings of the dilated electron propagator with application to 2Π CO− and 2B2g C2H4− shape resonances

The zeroth (Σ0), second order (Σ2), quasiparticle second order (Σ2q), diagonal two-particle one-hole Tamm Dancoff approximation (Σ2ph-TDA) and the quasiparticle diagonal 2ph-TDA (Σq2ph-TDA) decouplings have been applied to investigate the 2Π CO− and 2B2g C2H4− shape resonances. An examination of the resonant roots and the corresponding Feynman Dyson amplitudes (FDAs) reveals that the most economic and effective description is offered by the second order decoupling. The more demanding diagonal two-particle one-hole Tamm Dancoff approximation (2ph-TDA) is shown to be less effective and the quasiparticle decouplings are shown to be no better than the zeroth order (bivariational self-consistent field) approximation in the description of molecular shape resonances. The correlation and relaxation effects incorporated by the Σ2 and Σ2ph-TDA decouplings are shown to assist resonance formation by lowering the antibonding nature of the lowest unoccupied molecular orbitals (LUMOs) on the real line and by turning these into anionic diffuse orbitals suitable for metastable electron attachment for the optimal value of the complex scaling parameter. The use of complex resonance energies calculated here to construct a nonempirical optical potential for the investigation of vibrational dynamics of these resonances is suggested.

Parametric least squares approximation using gamma bases

We study the problem of linear approximation of a signal using the parametric gamma bases in L/sup 2/ space. These bases have a time scale parameter, which has the effect of modifying the relative angle between the signal and the projection space, thereby yielding an extra degree of freedom in the approximation. Gamma bases have a simple analog implementation that is a cascade of identical lowpass filters. We derive the normal equation for the optimum value of the time scale parameter and decouple it from that of the basis weights. Using statistical signal processing tools, we further develop a numerical method for estimating the optimum time scale. >

ガラス短繊維強化熱可塑性樹脂の微量無機添加物（酸化チタン）による引張強度低下に関するマイクロメカニックス的研究

Tensile strength of injection-molded short glass fiber reinforced thermoplastics was remarkably decreased by the addition of a slight amount of titanium dioxide (TiO2) . Generally it is explained that the strength deterioration is due to much shortening of glass fiber length under processing, since the hardness of TiO2 is higher than that of glass fibers. In this study, the influence of the addition of TiO2 (0.2 wt%) to short glass fiber reinforced polyamide 6 on the strength of glass fibers in the composite was investigated. The tensile strength of the composite containing TiO2 was fairly lower than that of the composite without TiO2, even if the glass fiber lengths in the composite were unchanged. However, numerous flaws were observed on the surface of glass fibers in the composite containing TiO2. After tensile test of the composites, the pull-out lengths of glass fibers were measured and the variation of Weibull moduli was estimated by using the data based on the Weibull weakest-link theory. As a result, the value of scale parameter decreased markedly by the addition of TiO2. Namely, it was found that the main factor of the strength deterioration of short glass fiber reinforced polyamide 6 containing TiO2 was weakening of glass fibers.

On the orbital picture of shape resonances using Feynman–Dyson amplitudes from different decouplings of the dilated electron propagator

The orbital picture of shape resonances is investigated by examining the radial charge density distributions calculated from resonant Feynman–Dyson amplitudes for the 2P shape resonances in e-Be, e-Mg, and e-Ca scattering using the zeroth (bivariational self-consistent field), second order and the diagonal two particle one hole-Tamm–Dancoff approximation decouplings of the dilated electron propagator. A comparison between the radial density distributions from the highest occupied and the resonant orbital/Feynman–Dyson amplitude(s) reveals an accumulation of the electron density near the target for optimal value of the complex scaling parameter. The nodal pattern of the radial distributions differs from that expected for the lowest unoccupied p orbitals but their dominant contribution to the charge density distribution is clearly seen. A study of the difference between the radial densities obtained from various decoupling schemes highlights the role of correlation and relaxation in the characterization of these resonances. The role of coordinate space span of the primitive Gaussian-type orbital basis in characterization of these resonances is discussed.

A least biased fuzzy clustering method

A new operational definition of cluster is proposed, and a fuzzy clustering algorithm with minimal biases is formulated by making use of the maximum entropy principle to maximize the entropy of the centroids with respect to the data points (clustering entropy). The authors make no assumptions on the number of clusters or their initial positions. For each value of an adimensional scale parameter /spl beta/', the clustering algorithm makes each data point iterate towards one of the cluster's centroids, so that both hard and fuzzy partitions are obtained. Since the clustering algorithm can make a multiscale analysis of the given data set one can obtain both hierarchy and partitioning type clustering. The relative stability with respect to /spl beta/' of each cluster structure is defined as the measurement of cluster validity. The authors determine the specific value of /spl beta/' which corresponds to the optimal positions of cluster centroids by minimizing the entropy of the data points with respect to the centroids (clustered entropy). Examples are given to show how this least biased method succeeds in getting perceptually correct clustering results. >

Linear or linear plus Coulomb potential for description of quarkonium spectra?

In previous works we explained theS andP-wave data on heavy quark spectroscopy for the spin-independent potential given by the combination of linear, harmonic or power-law and colour-Coulomb potentials. In the present work, we try to understand the same quarkonium spectra when the spin-independent part of the potential contains the linear potential only and the colour-Coulombic piece is treated perturbatively. We find that the present model cannot explain all the features ofS andP-wave data even at the cost of a large value of QCD scale parameter.

TESTS OF PERTURBATIVE QCD USING R, $\Gamma _h^Z $ AND EVENT TOPOLOGY MEASUREMENTS IN HADRONIC Z-DECAYS

The world data on R and [Formula: see text] is used to derive a value of the QCD scale parameter, free of hadronization and renormalization scale uncertainties, of [Formula: see text]. This value is then used to investigate the convergence of the QCD perturbation expansions for several different jet topology measures, with the choice [Formula: see text] of the renormalization scale. In most cases satisfactory convergence is observed. The overall consistency of all measurements of [Formula: see text] is also discussed. Although [Formula: see text] seems high, present data is consistent (17% C.L.) with a global world average value of [Formula: see text], [Formula: see text].

Angular dependence of J c and B c2 in the CVD-YBa 2Cu 3O 7−δ films

The field and the temperature dependence of J c at various angles were resistively measured using the high-J c YBa 2Cu 3O 7−δ films prepared by chemical vapor deposition. Both dependence of J c was described by the scaling law of the global pinning force, although the values of scaling parameter m for the temperature and the field dependence were slightly different. The temperature scaling law was well established for B//c-axis, while it deviated from the observed data in low temperature region below 60K for B⊥c-axis.

Properties of heavy quarkonia and related states

Mass levels and widths of very heavy quarkonia and similar onium resonances of squarks, color octet and sextet constituents are studied in the mass range of 50 to 1000 GeV. The heavy quark potential with QCD two-loop improved short-distance behavior that gives a good description of the charmonium and bottomonium spectra is used, and the results are given for several values of the QCD scale parameter Λ MS (4) in the range between 0.1 and 0.4 GeV. We present parametrizations for the first ten S-wave quarkonium resonances, which are relevant if the top quark is relatively light ( m t≲125 GeV) or if a heavy fourth-generation quark with suppressed weak decay rates exists. We also discuss the onset of coulombic behavior and the possible effects of Higgs boson exchange on superheavy quarkonia.

An evaluation of wind energy potential as a power generation source in Nigeria

Abstract In this work a statistical analysis of wind energy available in different parts of Nigeria is carried out, using Weibull distribution and 15 years of wind data. Twelve sites are selected in the four distinctive regions identified; 1.0–2.0, 2.1–3.0, 3.1–4.1 and >4.1 m/s. The results show the Weibull distribution, power and speed duration curves, the values of shape and scale parameters of the Weibull distribution, the speed frequency distribution and their cumulative duration in hours. The wind energy potential is evaluated for the use of rural communities in these regions. The cost benefit analysis shows the economic feasibility of using wind energy conversion systems for electric power generation and supply in the country.

Temperature dependence of lifetime statistics for single Kevlar 49 filaments in creep-rupture

Experimental data are presented for the strength and lifetime under constant stress of single Kevlar 49 aramid filaments at two elevated temperatures, 80 and 130° C. As seen in previously published work performed at room temperature (21 °C), the strength data could be fitted to a two-parameter Weibull distribution; increasing the temperature caused a decrease in the Weibull scale parameter while the shape parameter remained relatively constant, indicating a decrease in the mean strength but no change in strength variability. Lifetime experiments at both 80 and 130°C were performed at different filament stress levels, ranging from 55 to 92.5% of the Weibull scale parameter for short-term strength at that temperature. These data were fitted to a two-parameter Weibull distribution with large variability (scale parameter values ⩽ 1), and evaluated using an exponential kinetic breakdown model in the spirit of Eyring and Zhurkov. Using this model, activation energies in the neighbourhood of 80 kcal mol−1 (3.35 × 105 J mol−1 ) were obtained, suggesting that scission of the C-N bond plays the dominant role in fibre failure at longer times under constant stress.

Wind energy potential in Iraq

Ten years' wind data for nine locations inside Iraq and six outside it in the neighbouring countries were used to calculate the potential of wind energy in Iraq. The nine selected stations were used to draw the regional distribution of mean wind speed in Iraq. It was found that four distinctive regions exist 2.0 – 3.0, 3.1 – 4.0, 4.1 – 5.0, and greater than 5.1 m/s regions. A full statistical analysis has been carried out for each station which involved monthly average speed, annual values of shape and scale parameters of Weibull distribution, the average speed frequency, Weibull distribution, speed distribution and their cumulative duration in hours, and the diurnal pattern of wind spped of each location. It can be seen that one sixth of the country enjoys annual wind speed greater than 5.0 m/s. Wind farms could be used in Iraq to supply electricity to many parts.

Determination of the scale parameter ΛQCD from elastic electron-proton scattering at high Q2

The form factor predictions of perturbative QCD at asymptotic Q 2 and meson dynamics at low Q 2 are combined to fit the existing data on elastic electron-nucleon cross sections. Taking into account contributions due to the anomalous dimensions of the three-quark component in the nucleon, fits to the data give values of the QCD scale parameter Λ QCD in the range 100–250 MeV.

The use of scaled STO basis sets in SCF calculations on H? and Li+

LCAO SCF calculations on H– and Li+ have been made using uniformly scaled STO basis sets taken in either even-tempered or Clementi–Roetti forms. As in the earlier work on helium, the total energy profiles, as a function of the scaling parameter, show several minima at which the calculated electronic properties are very close in value to their Hartree–Fock counterparts. The global minimum moves towards smaller values of the optimum scaling parameter as the atomic number decreases. The least sensitive expectation values correspond to the energy of the occupied atomic orbital and 〈δ(r12)〉. In contrast, the energies of the unoccupied atomic orbitals decrease monotonically towards definite limiting values as the optimum value of the scaling parameter ranges from largest to smallest values. For He and H–, all unoccupied orbital energies decrease towards zero, whilst for Li+ the limiting energies are all different and negative and the number of such bound orbitals increases with the size of the basis set. The limiting energy of the lowest unoccupied orbital in Li+ corresponds to the energy of the occupied 2s orbital in neutral lithium. The overall pattern of the results suggests that it might be possible to select a basis set that will not only reproduce electronic properties of near-Hartree–Fock quality, but also provide a starting point for performing calculations on excited states.

極値解析の実プラント腐食問題への適用におけるパラメータ推定法による差異

The parameters of extreme value statistical analysis are calculated by several methods, for example, the method of least squares (MLS), minimum variance linear unbiased estimator method (MVLUE), and maximum likelihood estimator method (MLE). We have examined difference in value of the parameters estimated by the above three methods and compared the calculated maximum value with the actual value of corrosion rate for several cases in chemical process plants.In conclusion, MVLUE was the best method for estimating the maximum value of corrosion rate independent of kind of machines, atmosphere, types of corrosion and corrosion positions. The following relation was observed in the estimated values of scale parameter (α), MLS>MVLUE>MLE but no difference in the estimated value of location parameter (λ) was recognised among the above three methods.

Symmetry breaking gut phase transitions with irreversibilities

For some values of the GUT energy scale parameter, irreversibilities essentially modify the cosmological expansion and may drive inflation even without supercooling. Since in this case the GUT phase transition is affected too, a proper dynamical treatment of the evolution of the early universe is given.

Observations of beach cusps

Aagaard. Troels: Observations of beach cusps. Geografisk Tidsskrift 85: 27–31 Copenhagen, October 1985. Observations of beach cusps have been conducted under low-energy conditions on the northern coast of Zealand, Denmark. The distance between cusps showed consistently good correlation with values calculated from a hypothetical occurrence of synchronous or subharmonic edge waves. A relationship is implied between the edge wave frequency and the value of the surf scaling parameter. Supplementary observations from the southern coast of England indicate that the edge wave theory may not be adequate in explaining the distance between cusps on pocket beaches.