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Le Sahara (en الصحراء الكبرى , , « le grand désert », en berbère : ⵜⵉⵏⵉⵔⵉ Tiniri ou ⵜⵏⵔ Tenere) est un vaste désert chaud situé dans la partie nord du continent africain. Il s'étend sur d'ouest en est, de l'océan Atlantique à la mer Rouge, et couvre plus de (soit près de 30 % de la surface du continent africain), ce qui en fait la plus grande étendue de terre aride d'un seul tenant dans le monde. Le Sahara peut même être prolongé au-delà de la mer Rouge, les géographes parlant alors d'un grand « désert saharo-arabique ». Plus largement encore, le Sahara constitue la partie occidentale d'une vaste diagonale sèche qui s'étend des abords du fleuve Sénégal à la Mongolie. Plus vaste désert chaud du monde, il divise le continent d'est en ouest. Il couvre d'immenses étendues et s'étend sur le territoire de dix États : l'Algérie, l'Égypte, le Maroc, la Libye, la Tunisie, la Mauritanie, le Niger, le Mali, le Tchad, le Soudan, ainsi que sur le territoire contesté du Sahara occidental. Le

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Chargement

Constructing the desert. Hotel and coach station (Ouarzazate, Maroc)

Pietro Berta, Adèle Moret

Desertification process keeps on expanding, particularly on the African continent, arid areas cover one third of the surface. At the same time, the world human population increases exponentially. For these reasons, it is important to keep on exploiting these desert zones. Ouarzazate is situated in the south of Morocco in a sub-desert climate. The city is nicknamed “Door of the desert” because of its strategic location: it is situated at the junction of the two roads, which give accessibility to the south of Morocco and the Sahara desert. The region is well known for its architectural patrimony and more recently for the cinema activities. These two different domains make increase the number of visitors in this part of the country and there will soon be a lack of host infrastructure including hotels. The project, a hotel and a coach station, doesn't want to be closed-off on itself, but to take place in the city centre to benefit of the existing activities; at the same time the two programs are close to the main crossroad of the region. This situation is accorded with the way tourists travel in the region: moving a lot in order to discover a maximum of sites spread in the south and staying a short time in the same place. The hotel is inspired by the caravanserai, which was a roadside inn along the trade routes where travellers could rest and recover from the day's journey. It supported the flow of commerce, information and people. It was a place where travellers could acquire new supplies and there were also shops where merchants could dispose of some of their goods. The issue of this project in the desert is to build in a sustainable way using contemporary building construction modes being in the same time inspired by vernacular architecture.

2009

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Multiobjective Optimisation of integrated energy systems for remote communities considering economic and LCA factors

Daniel Favrat, Xavier Pelet

Resources both physical and financial are scarce in most developing countries while environmental concerns are growing requiring a greater effort to rationally plan investments. Nowadays the methods for designing, planning and managing integrated energy systems, while holistically considering the major economic and environmental factors, are still embryonic. However, the first phase of the design is often crucial if we want to aim at a better resource management and at the reduction of energy consumption together with reduced environmental impact. Considering integrated energy systems implies dealing with complex systems in which the synergy between the various components is exploited at best. The context of isolated communities further increases the difficulties when considering the long distance of transportation required to supply fossil fuels, the constraints of not being connected to a national network and the locations in very precarious environments, with limited or inexistent resources except for solar. This paper illustrates a holistic method to rationalize the design of energy integrated systems accounting for Life Cycle Analysis parameters (CST method). It is based on a superstructure (collection of models of all envisaged technologies) using a multi-modal and multi-objective evolutionary algorithm. The models include both solar power technologies as well as conventional Diesel electric generators. The approach is applied to the supply of energy services to an oasis in the Sahara desert. The study shows that the economic implementation of renewable energy (solar) is even more difficult, compared to Diesel based solutions, in cases of isolated communities with high load variations.

2007

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Atmospheric acidification of mineral aerosols: A source of bioavailable phosphorus for the oceans

Athanasios Nenes

Primary productivity of continental and marine ecosystems is often limited or co-limited by phosphorus. Deposition of atmospheric aerosols provides the major external source of phosphorus to marine surface waters. However, only a fraction of deposited aerosol phosphorus is water soluble and available for uptake by phytoplankton. We propose that atmospheric acidification of aerosols is a prime mechanism producing soluble phosphorus from soil-derived minerals. Acid mobilization is expected to be pronounced where polluted and dust-laden air masses mix. Our hypothesis is supported by the soluble compositions and reconstructed pH values for atmospheric particulate matter samples collected over a 5-yr period at Finokalia, Crete. In addition, at least tenfold increase in soluble phosphorus was observed when Saharan soil and dust were acidified in laboratory experiments which simulate atmospheric conditions. Aerosol acidification links bioavailable phosphorus supply to anthropogenic and natural acidic gas emissions, and may be a key regulator of ocean biogeochemistry. © 2011 Author(s).

2011

Chargement

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The course equips students with a comprehensive scientific understanding of climate change covering a wide range of topics from physical principles, historical climate change, greenhouse gas emissions, the IPCC assessment to future scenarios and climate action.

ENV-221: Hydrology for engineers

"Hydrology for Engineers" is an introduction to the study of floods, droughts and a fair distribution of water. The course will introduce basic hydrologic concepts and methods: probability and statistics, surface and subsurface hydrological processes

ENV-424: Water resources engineering

Water resources engineering designs systems to control the quantity, quality, timing, and distribution of water to support human demands and the needs of the environment.

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