Ground-based measurements of UV Index (UVI) at Helwan

AbstractOn October 2010 UV Index (UVI) ground-based measurements were carried out by weather station at solar laboratory in NRIAG. The daily variation has maximum values in spring and summer days, while minimum values in autumn and winter days. The low level of UVI between 2.55 and 2.825 was found in December, January and February. The moderate level of UVI between 3.075 and 5.6 was found in March, October and November. The high level of UVI between 6.7 and 7.65 was found in April, May and September. The very high level of UVI between 8 and 8.6 was found in June, July and August. High level of radiation over 6months per year including 3months with a very high level UVI. According to the equation {UVI=a[SZA]b} the UVI increases with decreasing SZA by 82% on a daily scale and 88% on a monthly scale. Helwan exposure to a high level of radiation over 6months per year including 3months with a very high level UVI, so it is advisable not to direct exposure to the sun from 11am to 2:00pm

Embedded Coding of Astronomical Images

Recursive partitioning of significant wavelet sub-bands (RPSWS) is an embedded rate scalable wavelet-based image coding algorithm. The RPSWS coder produces a fully embedded bit stream and encodes the image to exactly the desired bit rate (precise rate control). This paper investigates the applicability and the reliability of the RPSWS coder for coding astronomical images. Various types of astronomical images were compressed at different bit-rates using the RPSWS coder. The results were compared to the set partitioning in hierarchal trees coder (SPIHT), a well known embedded image corder. The comparison of the performance of the two algorithms was based on quantitative rate-distortion evaluations and subjective assessments of image quality.

Exposure to air pollutants among cyclists: A comparison of different cycling routes in Perth, Western Australia

Cycling is often promoted as a means of reducing vehicular congestion, greenhouse gases, noise and air pollutant emissions in urban areas. It is also endorsed as a healthy means of transportation in terms of reducing the risk of developing a range of physical and psychological conditions. However, people might not be aware of the negative health impacts of cycling near heavy traffic. This study aimed to compare personal exposure with particulate air pollution among cyclists commuting in Perth, Western Australia. The study involved 122 number of cyclists riding bicycles in four different routes: two routes within community areas (Route 1 and Route 2) and two routes near freeways (Route 3 and Route 4). The participants were males and females aged between 20 and 55 years with the selection criteria including non-smokers who cycle at least 150 km/week—ideally along one of the four study routes. Personal exposure of respirable particulate air pollution during cycling at the high and low level of exertions (self-perceived) were assessed. Ambient concentrations of selected air pollutants were also measured at each cycling route. We found that Route 3 appeared to be the most polluted route and concentrations of nitrogen dioxide and sulphur dioxide exceeded the Australian standards. This study concluded that personal exposure to respirable particles was influenced by the speed, time of cycling and seasonal variation