Étude de l’évolution du littoral de la baie d’El Jadida (Maroc) par photo-interprétation

La baie d’El Jadida se situe sur la façade atlantique du Maroc (entre 33° 15’ 00’’ et 33° 21’ 40’’ de latitude Nord, 8° 18’ 00’’ et 8° 30’ 00’’ de longitude Ouest). Elle constitue un grand système sableux fortement marqué par la dynamique littorale. L’utilisation des photographies aériennes permet de déterminer d’une part, l’évolution du trait de côte à l’embouchure de l’Oum Rbia à long terme (de 1949 à 1996) et d’autre part.de mesurer l’évolution de l’ensemble du littoral de la baie El Jadida à moyen terme (de 1988 à 1997). Les résultats de l’étude diachronique confirment la variabilité spatio-temporelle et l’évolution du littoral de la baie d’El Jadida avec des zones en érosion et d’autres en accumulation. L’analyse des variations des traits de côte, à moyen terme, ne montre pas des modifications importantes. Les seuls changements ont été enregistrés au niveau des unités morphologiques composant ce littoral (plage aérienne, dunes,…). L’évolution du trait de côte à long terme se caractérise par une forte variabilité dans le secteur de l’estuaire de l’Oum Rbia. La période d’érosion la plus importante se situe entre 1949 et 1996 avec un taux de recul de 45 m (1,28 m/an). Durant cette même période, on distingue aussi une variabilité spatiale qui se traduit par l’existence de deux secteurs très différents : le premier est caractérisé par une forte érosion (plage de la rive droite) et le deuxième est favorisé par des accumulations importantes (flèche sableuse de la rive gauche).Mots-clés : baie d’El Jadida, plage, estuaire, trait de côte, évolution morphologique, évolution diachronique, flèche sableuse, Maroc. Study of coastline evolution of the El Jadida bay (Morocco) by photo-interpretationEl Jadida bay, is located on the middle of the Atlantic coast of Morocco (between 33° 15’ 00’’ and 33° 21’ 40’’ North and between 8° 18’ 00’’ and 8° 30’ 00’’ West), constitute a large sandy stock strongly marked by the littoral dynamic. The use of the aerial photographs permit to identify the coast evolution to the Oum Rbia estuary (of 1949 to 1996) and to measure the littoral of the bay El Jadida evolution in medium-term. The results of this diachronic study confirm space and time variability in the littoral of bay evolution with deepening reach’s and others of sedimentation. The coastline variation analysis in medium-term doesn’t give satisfactory results. The only changes were registered at the morphological units of the coast (aerial beach, dunes, ... ). The coastline evolution in the long-term coast is characterized by a strong variability in the Oum Rbia estuary. The period of the most important erosion ranges between 1949 and 1996 with a rate of retreat of 45 m (1.28 m/an). During this period, we can also notice a space variability which results in the existence of two very different sectors: the first is characterized by strong erosion (beach of Right Bank) and the second is characterized by accumulations (sandy arrow of left bank).Keywords : El Jadida bay, estuary, coastline, morphologic evolution, diachronic evolution, sandy arrow, Morocco

Structure and Dielectric Properties of Cerium Doped Lead Titanate Ceramics

Sintered ceramic powders of cerium-doped lead titanate (Pbx/2+1CexTi1-xO3) ceramics with different Ce dopant concentration in the range (x=0-0.1) have been prepared using a sol-gel chemical route. The sol-gel technique is known to offer better purity and homogeneity, and can yield stoichiometric powders with improved properties at relatively lower processing temperature in comparison to conventional solid-state reaction. X-ray diffraction (XRD) scanning electronic microscope (SEM) and Raman spectroscopy studies have been carried out to identify the crystallographic structure and phase formation. The refinement of the structural parameters was carried out by the Rietveld method. PCT exhibit tetragonal symmetry with the perovskite structure. The dielectric properties as a function of frequency, and phase transition studies on sintered ceramics Pbx/2+1CexTi1-xO3 (x=0.03) has been investigated in detail over a wide temperature range 30-500°C and the results are discussed. Keywords:  A. ceramics; B. x-ray diffraction; C. Raman spectroscopy; D. dielectric; C. properties; E. Ce-modified

Reflections on a degree initiative: the UK's Birmingham Royal Ballet dancers enter the University of Birmingham

This paper provides an opportunity to share experiences and perceptions of the first 5 years of a degree programme for professional dancers. A partnership developed in the mid-1990s between the UK's Birmingham Royal Ballet and the University of Birmingham, Westhill (now School of Education), to provide a part-time, post-experience, flexible study programme for full-time Company dancers. This is the first 'company customised' higher education programme to dovetail studies around rehearsal, performance and touring schedules. Methodology is based on a narrative by the author, informed by ongoing internal and external evaluations, in-depth interviews with dancers and Company managers, documentation and secondary sources. Outcomes indicate that the programme has made a positive difference to the Company, to the dancers and to the wider education and dance/arts world

Seasonal Variation (Winter vs. Summer) Crustacean Fauna of the Oualidia Lagoon, Morocco

The Oualidia lagoon on the Atlantic coast of Morocco provides important ecosystem services such as aquaculture, fisheries, tourism and high ecological and biological productivity. This is the first study to describe the spatio-temporal distribution of the crustacean community and potential controlling factors in the coastal waters of the Oualidia lagoon. Crustaceans were sampled with a Van Veen grab during two surveys in winter and summer 2013, and taxonomic composition and diversity were determined at 43 sampling sites. Of the eighteen crustacean taxa recorded, fifteen were new to Oualidia Lagoon. Sphaeroma serratum was the most abundant species in both seasons. Organic matter and chlorophyll a content were higher, temperature and salinity were lower in winter than in summer. The structure of the crustacean assemblages was characterised by the formation of two main clusters, organised according to a downstream gradient. Canonical Correspondence Analysis (CCA) showed that granulometry, organic matter and salinity strongly influenced the distribution pattern of crustaceans in the lagoon

USING GIS AND PHOTOGRAMMETRY FOR ASSESSING SOLAR PHOTOVOLTAIC POTENTIAL ON FLAT ROOFS IN URBAN AREA CASE OF THE CITY OF BEN GUERIR / MOROCCO

Renewable energy sources are at the forefront of political discussions around the world because of the scarcity of fossil fuels and climate change caused by the accumulation of greenhouse gases. By 2030, Morocco will cover 52% of these energy needs through renewable energies, in order to preserve the environment (COP 22). This paper aims to estimate the potential of photovoltaic solar energy from flat roofs in the city of Ben Guerir, Morocco using remote sensing and GIS data. To achieve this goal, vector orthophoto resulting from the photogrammetric restitution acquired in 2015 were used to generate a 3D model (DSM). The annual solar irradiation is calculated by the analyser of the solar tool. Each roof is calculated based on algorithms for the most common solar panel technologies (mono-si and poly-si). The applicability of this methodology has been demonstrated in the urban area of Benguerir, Morocco, and can be widespread in any other region of the world. The results obtained for a total roofing surface of 135 Ha, i.e. more than 345 Gwh of electricity annually generate. For an average roof of 60 m2 that could supply 5 to 6 households; A planned investment between 118,218 and 167,296 DH, and an annual maintenance charge of 2%. This study may be an initial assessment of solar potential in the city, which can be used to support the management decision regarding investment in the urban solar system

Comments on Marine Litter in Oceans, Seas and Beaches: Characteristics and Impacts.

Marine litter is observed along shorelines, pelagic, benthic marine and lake systems all around the globe. On beaches, litter creates aesthetic and related economic problems because a clean beach is one of the most important characteristics of a seaside resort required by visitors. Litter can reach the marine environment from marine or land activities but it is estimated that 80% originates from land-based sources. The marine-based sources of litter include all types of sea-going vessel and offshore installations, the most abundant plastic debris in the oceans being derelict (lost or improperly discarded) fishing gear. Most of marine litter is composed by plastics due to their greater durability and persistence, combined with plastic rising production and low rates of recovery. Special importance is linked to microplastics because their ubiquity, persistence, mechanical effects on biota and the ecosystem because of ingestion by organisms and their toxic potential. As plastics degrade they can release toxic chemicals initially incorporated during their manufacturing or persistent organic pollutants and heavy metals sorbed to their surfaces in the environment. Such toxins can disrupt endocrine functions and cause harmful reproductive and developmental effects in aquatic animals

Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques

race metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources