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Noise barriers are one of the primary means in noise abatement for traffic-related noise in proximity of roads and railways. While the efficiency in noise absorption and noise insulation is evaluated experimentally with different methods [1,2,3], simulations are a helpful and cost-saving tool in predicting and planning new noise barrier solutions. In the following paper non-standard noise barriers have been analysed with the help of BEM simulations, with focus on the tunability of the barrier. [ABSTRACT FROM AUTHOR]

High-resolution measurements of the π ← Π Q-branch of pure N[sub 2]O near 1160 cm[sup -1] were made using a difference-frequency spectrometer with resolution of 5 × 10[sup -5] cm[sup -1] and a signal-to-noise ratio of 2000:1. Lines Q18F through Q12E have been recorded in a single scan, at room temperature and at pressures ranging from 1 to 130 torr. The spectra are analyzed up to 23 torr on a line-by-line basis using a hard collision profile including Dicke narrowing and line mixing. Since the separation of the central lines of this double-sided Qbranch is of the same order of magnitude with the collisional broadening, line mixing is considered in the analysis even at 1 tort and its dependence with pressure is studied. [ABSTRACT FROM AUTHOR]

A practical matrix-based formalism for solving the master equation for a spectral line is applied to the P(2) transition in the fundamental band of carbon monoxide perturbed by argon. The method assumes that the effect of intermolecular collisions on the internal relaxation of the molecules is uncorrelated with the effect of those collisions on the translational motion of the molecules. Comparison with high-resolution line shape measurements reveals that at low pressures, the omission of statistical correlation leads to a miscalculation of the shape of the line. [ABSTRACT FROM AUTHOR]