in this work some quantitative structure activity relationship models were developed for prediction of three bioenvironmental parameters of 28 volatile organic compounds, which are used in assessing the behavior of pollutants in soil. these parameters are; half-life, non dimensional effective degradation rate constant and effective péclet number in two type of soil. the most effective descripto...

We present a short review of the current quasar (QSO) absorption line constraints on possible variation of the fine structure constant, α ≡ e 2 /¯ hc. Particular attention is paid to recent optical Keck/HIRES spectra of 49 absorption systems which indicate a smaller α in the past [1, 2]. Here we present new preliminary results from 128 absorption systems: ∆α/α = (−0.57 ± 0.10) × 10 −5 over the ...

We put bounds on the variation of the value of the fine structure constant α, at the time of Big Bang nucleosynthesis. We study carefully all light elements up to 7Li. We correct a previous upper limit on |∆α/α| estimated from 4He primordial abundance and we find interesting new potential limits (depending on the value of the baryon-to-photon ratio) from 7Li, whose production is governed to a l...