No abstract

This paper presents the hazard mapping of groundwater in the Tlemcen urban area (TUA). First, we identified the potential pollution sources (of industrial, agricultural and urban origins) existing in the studied area that can affect the karstic groundwater. It is the most important reserve and the main source of drinking water supply of this area. Then, we mapped all these hazards on a topographic map at scale 1:25,000. Finally, a classified hazard map was established. This investigation clearly shows that the groundwater of TUA is far from being safe from the risk of pollution. Adequate and urgent actions must be taken in order to eliminate or to reduce the risks of contamination of this water resource which is highly vulnerable because of the lack of protection perimeters.

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Lightweight yet precise, temperature control protocols are critical in a variety of applications. This is especially true in space where weight and volume are at a premium and reliability is paramount. In space, complex processes to manage the heat fluxes generated from within and absorbed from space by the spacecraft are usually implemented. Surfaces having different heat fluxes might need to be controlled separately and maintained at different temperatures. The work presented in this paper evaluates a novel laser surface modification process to form micro-column arrays (MCA) on any material for use as highly adaptive radiators. The MCA-structured surfaces have experimentally been shown to have excellent emissive properties. Finite element methods have been used to simulate the temperature profiles for surfaces with and without MCA compared to pin fin structures as a function of input heat flux density. In the case of Ti, our models show that pin fin arrays are better heat radiating surfaces than equivalent MCA structures with cone-like profiles. Such structures, however, are difficult to modify and usually require complicated and expensive fabrication processes. Overall, MCA structures are shown to allow good control over base surface temperature for varying heat fluxes and different MCA aspect ratios. For Ti, under steady state conditions, an aspect ratio of 12 has been shown to be optimal for surface heat reduction. Preliminary experimental results show that the temperature drop is inline with that theoretically predicted.