64,668 research outputs found
Practical Data Correlation of Flashpoints of Binary Mixtures by a Reciprocal Function: The Concept and Numerical Examples
Simple data correlation of flashpoint data of binary mixture has been
developed on a basic of rational reciprocal function. The new approximation
requires has only two coefficients and needs the flashpoint temperature of the
pure flammable component to be known. The approximation has been tested by
literature data concerning aqueous-alcohol solution and compared to
calculations performed by several thermodynamic models predicting flashpoint
temperatures. The suggested approximation provides accuracy comparable and to
some extent better than that of the thermodynamic methods.Comment: 6 pages and 5 tables IN PRESS; Thermal Science vol. 15, issue 3, 201
Calibration and improved prediction of computer models by universal Kriging
This paper addresses the use of experimental data for calibrating a computer
model and improving its predictions of the underlying physical system. A global
statistical approach is proposed in which the bias between the computer model
and the physical system is modeled as a realization of a Gaussian process. The
application of classical statistical inference to this statistical model yields
a rigorous method for calibrating the computer model and for adding to its
predictions a statistical correction based on experimental data. This
statistical correction can substantially improve the calibrated computer model
for predicting the physical system on new experimental conditions. Furthermore,
a quantification of the uncertainty of this prediction is provided. Physical
expertise on the calibration parameters can also be taken into account in a
Bayesian framework. Finally, the method is applied to the thermal-hydraulic
code FLICA 4, in a single phase friction model framework. It allows to improve
the predictions of the thermal-hydraulic code FLICA 4 significantly
The thrust and heavy-jet mass distributions in the two-jet region
Dressed Gluon Exponentiation (DGE) is used to calculate the thrust and the
heavy-jet mass distributions in e+e- annihilation in the two-jet region. We
perform a detailed analysis of power corrections, taking care of the effect of
hadron masses on the measured observables. In DGE the Sudakov exponent is
calculated in a renormalization-scale invariant way using renormalon
resummation. Neglecting the correlation between the hemispheres in the two-jet
region, we express the thrust and the heavy-jet mass distributions in terms of
the single-jet mass distribution. This leads to a simple description of the
hadronization corrections to both distributions in terms of a single shape
function, whose general properties are deduced from renormalon ambiguities.
Matching the resummed result with the available next-to-leading order
calculation, we get a good description of the thrust distribution in a wide
range, whereas the description of the heavy-jet mass distribution, which is
more sensitive to the approximation of the phase space, is restricted to the
range rho_H<1/6. This significantly limits the possibility to determine alpha_s
from this observable. However, fixing alpha_s by the thrust analysis, we show
that the power corrections for the two observables are in good agreement.Comment: minor modifications; 46 pages, 11 post-script figures; to appear in
Nucl. Phys.
Reliability analysis and micromechanics: A coupled approach for composite failure prediction
This work aims at associating two classical approaches for the design of composite materials: first, reliability methods that allow to account for the various uncertainties involved in the composite materials behaviour and lead to a rational estimation of their reliability level; on the other hand, micromechanics that derive macroscopic constitutive laws from micromechanical features. Such approach relies on the introduction of variabilities defined at the microscale and on the investigation of their consequences on the material macroscopic response through an homogenization scheme. Precisely, we propose here a systematic treatment of variability which involves a strong link between micro- and macroscales and provides a more exhaustive analysis of the influence of uncertainties. The paper intends to explain the main steps of such coupling and demonstrate its interests for material engineering, especially for constitutive modelling and composite materials optimization. An application case is developed throughout on the failure of unidirectional carbon fibre-reinforced composites with a comparative analysis between experimental data and simulation results
Improved radiative corrections for (e,e'p) experiments: Beyond the peaking approximation and implications of the soft-photon approximation
Analysing (e,e'p) experimental data involves corrections for radiative
effects which change the interaction kinematics and which have to be carefully
considered in order to obtain the desired accuracy. Missing momentum and energy
due to bremsstrahlung have so far always been calculated using the peaking
approximation which assumes that all bremsstrahlung is emitted in the direction
of the radiating particle. In this article we introduce a full angular Monte
Carlo simulation method which overcomes this approximation. The angular
distribution of the bremsstrahlung photons is reconstructed from H(e,e'p) data.
Its width is found to be underestimated by the peaking approximation and
described much better by the approach developed in this work.Comment: 11 pages, 13 figure
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