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[en] New distances to the supernova remnants (SNRs) G31.9+0.0 and G54.4−0.3 have been found. The analysis method uses H i absorption spectra and CO channel maps. Individual H i channel maps are used to verify absorption features in the H i absorption spectrum or to determine if they have noise. Both of the SNRs are associated with molecular clouds so accurate kinematic velocities are determined. The H iabsorption is used to resolve the kinematic distance ambiguity. The resulting new distance for G31.9+0.0 is 7.1 ± 0.4 kpc and for G54.4−0.3 it is 6.6 ± 0.6 kpc. These are significant revisions to the previous values.
[en] In this paper, we analyze 1420 MHz continuum and H i observations of the supernova remnant (SNR) 3C 397 (G41.1-0.3). The H i absorption spectra show clear absorption up to the tangent point velocity and also the absence of absorption at 50–60 km s"−"1. This yields lower and upper limits to the distances of 6.3 ± 0.1 and 9.7 ± 0.3 kpc, which are better and more robust than previous estimates. We apply generalized SNR models to 3C 397, including the ejecta-dominated phase and the transition-to-Sedov phase. Using emission measures from the X-ray and mean gas density from the infrared, we show that the hard X-ray component has the dominant filling factor and the soft X-ray component has a very small filling factor. The models are required to be consistent with 3C 397's measured properties, including the observed shock temperatures and shock radii. Consistent models are found if 3C 397 has a distance in the range of ≃8–9.7 kpc. For an 8 kpc distance, the estimated age is ≃1350 years and the explosion energy is 1.0 × 10"5"1 erg, while for 9.7 kpc, the the most probable age is ≃1750 years and the energy 1.5 × 10"5"1 erg
[en] This paper describes a study conducted in the lighting sector of office buildings as a part of a broader research study aimed at developing building codes for Sri Lanka addressing lighting as well as thermal comfort in order to optimise the use of electricity within these buildings. The study covered different tasks performed in office buildings and the optimum lighting levels required to perform these tasks in the office environment in Sri Lanka. Also, it included assessing the visual performance of people involved in different activities under varying illumination levels in a controlled environment and a comparison of these optimum lighting levels with international standards. It can be seen that the required optimum lighting levels are generally lower in Sri Lanka in comparison to specified standard levels, and this scenario is likely to be similar in other developing countries too. These findings clearly emphasise the need to adopt lighting standards most appropriate to local conditions, in turn helping improve the energy efficiency within buildings