The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform
V. I. Tretyak - One of the best experts on this subject based on the ideXlab platform.
-
Semi-Empirical Calculation of quenching factors for scintillators: new results
EPJ Web of Conferences, 2014Co-Authors: V. I. TretyakAbstract:New results of Calculation of quenching factors for ions in scintillators in Semi-Empirical approach described in [1] are presented. In particular, they give additional arguments in favour of hypothesis that quenching factors for different particles can be described with the same Birks factor kB , if all the data were collected in the same conditions and processed in the same way.
-
Semi-Empirical Calculation of quenching factors for scintillators: new results
arXiv: Nuclear Experiment, 2013Co-Authors: V. I. TretyakAbstract:New results of Calculation of quenching factors for ions in scintillators in Semi-Empirical approach described in [V.I. Tretyak, Astropart. Phys. 33 (2010) 40] are presented. In particular, they give additional arguments in favour of hypothesis that quenching factors for different particles can be described with the same Birks factor kB, if all the data were collected in the same conditions and processed in the same way.
-
Semi-Empirical Calculation of quenching factors for ions in scintillators
Astroparticle Physics, 2010Co-Authors: V. I. TretyakAbstract:Abstract Semi-Empirical method of Calculation of quenching factors for scintillators is described. It is based on classical Birks formula with the total stopping powers for electrons and ions which are calculated with the ESTAR and SRIM codes, respectively. Method has only one fitting parameter (the Birks factor kB) which can have different values for the same material in different conditions of measurements and data treatment. A hypothesis is used that, once the kB value is obtained by fitting data for particles of one kind and in some energy region (e.g. for a few MeV α particles from internal contamination of a detector), it can be applied to calculate quenching factors for particles of another kind and for another energies (e.g. for low energy nuclear recoils) if all data are measured in the same experimental conditions and are treated in the same way. Applicability of the method is demonstrated on many examples including materials with different mechanisms of scintillation: organic scintillators (solid C 8 H 8 , and liquid C 16 H 18 , C 9 H 12 ); crystal scintillators (pure CdWO 4 , PbWO 4 , ZnWO 4 , CaWO 4 , CeF 3 , and doped CaF 2 (Eu), CsI(Tl), CsI(Na), NaI(Tl)); liquid noble gases (LXe). Estimations of quenching factors for nuclear recoils are also given for some scintillators where experimental data are absent ( CdWO 4 , PbWO 4 , CeF 3 , Bi 4 Ge 3 O 12 , LiF, ZnSe).
H. Bonadeo - One of the best experts on this subject based on the ideXlab platform.
-
Molecular structure and dynamical properties of C36: a Semi-Empirical Calculation
Chemical Physics Letters, 1999Co-Authors: E. Halac, E. Burgos, H. BonadeoAbstract:Abstract We have explored possible molecular structures and calculated the vibrational properties of the newly synthesized C 36 fullerene. We used a Semi-Empirical covalent potential that has been shown to reproduce these properties well in C 60 , C 70 , diamond and graphite. In agreement with ab initio Calculations, we find that D 6h and D 2d structures are the most stable. Using our Semi-Empirical potential we obtain infrared frequencies in the range of those observed for the crystal powder. We also calculate the Raman spectrum on the basis of the band polarizability model.
Laurence S. Rothman - One of the best experts on this subject based on the ideXlab platform.
-
Semi-Empirical Calculation of air-broadened half-widths and air pressure-induced frequency shifts of water-vapor absorption lines
Journal of Quantitative Spectroscopy and Radiative Transfer, 2005Co-Authors: D. Jacquemart, Robert R. Gamache, Laurence S. RothmanAbstract:Abstract This paper describes a Semi-Empirical Calculation of the air-broadened half-widths and the air pressure-induced frequency shifts for the H216O isotopologue. This Semi-Empirical Calculation is based on fits of several recent high-quality measurements and theoretical Calculations to the first-order terms in the expansion of the complex Robert–Bonamy (CRB) equations, which yields a second- and first-order polynomial function of the differences in the upper- and lower-state vibrational quantum numbers for the half-width and line shift, respectively. The aim of this work was to obtain a complete set of air-broadened half-widths and air pressure-induced frequency shifts for transitions of H216O present in the HITRAN database from microwave to the visible in order to supplement the observed and calculated values. For around 700 sets of rotational quantum numbers ( J ′ K a ′ K c ′ ← J ″ K a ″ K c ″ ), Semi-Empirical coefficients describing the vibrational dependence of the air-broadened half-widths and the air pressure-induced frequency shifts have been obtained directly from the fit of experimental and/or theoretical data. The accuracy of the parameters deduced from this Calculation is estimated to be between 5% and 10% for the air-broadened half-widths and between 0.001 and 0.01 cm - 1 atm - 1 for the air pressure-induced frequency shifts. For sets of rotational quantum numbers for which either none or insufficient experimental/theoretical data were available to deduce a vibrational dependence, further approximations have been used to obtain a complete set of Semi-Empirical coefficients.
K.j. Chou - One of the best experts on this subject based on the ideXlab platform.
-
Semi-Empirical Calculation of probabilities of radical formation at various sites in a 2,6,10-trimethyl undecane
Polymer, 1994Co-Authors: P.s. Subramanian, Y.h.r. Jois, J.b. Harrison, K.j. ChouAbstract:Abstract Semi-Empirical Calculations were done on a 2,6,10-trimethyl undecane to determine the activation energy for radical formation at various carbon sites. The results obtained were compared with probability of radical formation determined experimentally.
Felipe Pedro Álvarez Rabanal - One of the best experts on this subject based on the ideXlab platform.
-
On the significance of the climate-dataset time resolution in characterising wind-driven rain and simultaneous wind pressure. Part II: directional analysis
Stochastic Environmental Research and Risk Assessment, 2017Co-Authors: José M. Pérez-bella, Javier Domínguez-hernández, Juan J. Del Coz-díaz, Enrique Cano-suñén, Felipe Pedro Álvarez RabanalAbstract:Both Semi-Empirical methods and CFD simulations use real climate datasets as a basis for determining the building facade exposure to wind-driven rain and simultaneous wind pressure. The time resolution of these datasets and the number of variables considered (commonly rainfall intensity, wind speed and wind direction) determine the required Calculation effort and the accuracy of the result. Omitting the wind direction, a former article (Part I of this research) has analysed the effect of this time resolution on two scalar exposure indices obtained by Semi-Empirical methods: driving rain index (aDRI) and driving-rain wind pressure (DRWP). However, the wind direction during precipitation events also causes significant exposure variations between possible facade orientations. Thus, it is also necessary to clarify the influence of the time resolution of the dataset, on the accuracy of the directional Semi-Empirical Calculation of aDRI and DRWP. To meet this challenge, the article examines 10-min climate records collected between 2001 and 2016 at 6 Spanish locations, uses them to obtain hourly, daily, monthly and annual datasets, and analyses the accuracy of the directional exposure indices associated with each time resolution. The results show that a daily dataset would allow identifying the most exposed orientation with an error less than 45°. However, even the hourly datasets cause errors close to 10% in the exposure values identified on each facade orientation. Finally, adjustment relationships that allow estimating the maximum value of directional exposure from simple scalar indices are obtained.
