164 research outputs found
Utilisation Du Sig Dans L’analyse Morphometrique Et La Prioritisation Des Sous-Bassins Versants De Oued Inaouene (Nord-Est Du Maroc)
The present work focuses on the prioritization of the wadi Inaouène watershed based on morphometric analysis. The river system was extracted and thirteen sub-catchment basins have been delineated from a DTM using open source software. The following morphometric parameters were calculated for each sub-basin stream length (Lu) and the average length (Lsm), flow length ratio (RL), bifurcation ratio (Rb), medium bifurcation ratio (RBM), drainage density (Dd), drainage texture (T), the flow rate (Fs), elongation rate (Re), circularity ratio (Rc), form factor (Ff), topography and terrain ratio. By combining the values of these parameters we have classified the sub-watersheds in three prioritization categories: high grade (SBV01, SBV04, SBV05, SBV06, SBV11 and SBV12), is subject to a maximum soil erosion, which requires immediate action to prevent possible natural hazards, the Average category (SBV02, SBV03, SBV07, SBV08, SBV09 and SBV10) and low grade (SBV13)
UTILISATION D’UN MODELE HYBRIDE BASE SUR LA RLMS ET LES RNA-PMC POUR LA PREDICTION DES PARAMETRES INDICATEURS DE LA QUALITE DES EAUX SOUTERRAINES CAS DE LA NAPPE DE SOUSS-MASSA- MAROC
This work describes a new approach to the prediction of the parameters (microbiological, physical-chemical) groundwater quality indicators in the water table of Souss-Massa Morocco. The originality of this work lies in the application of a hybrid model based on the Stepwise Multiple Linear Regression and Neural Networks Multilayer Perceptron type. During the first stage, conventional statistical models namely the Stepwise Multiple Linear Regression was applied to a database that consists of eleven vectors as input vectors of the model and three vectors as the model output vectors in order to optimize the explanatory variables. In a second step, the optimized data base in the first step was used to construct a non recurring multi-layer network, the weights of the network connections are determined using the gradient back propagation algorithm. The data used as a database (learning, testing and validation) of the hybrid model are those relating to the analysis of 52 groundwater samples collected at several stations distributed in space and in time, of the groundwater Souss-Massa Morocco. The dependent variables (to explain or predict), which are three in number, are the Electrical Conductivity EC, the amount of Fecal Coliforms CF and Organic Matter MO
Heliocentric Escape and Lunar Impact from Near Rectilinear Halo Orbits
Spacecraft departing from the Gateway in a Near Rectilinear Halo Orbit (NRHO) experience gravitational forces from the Moon, the Earth, and the Sun, all of which can be simultaneously significant. These complex dynamics influence the post-separation risk of recontact with the Gateway and the eventual destinations of the departing spacecraft. The current investigation examines the flow of objects leaving NRHOs in the Bicircular Restricted Four-Body Problem, and results are applied to heliocentric escape and lunar impact trajectories in a higher-fidelity ephemeris model. Separation maneuver magnitude, direction, and location are correlated with risk of recontact with the Gateway and successful departure to various destinations
Disposal Trajectories from Near Rectilinear Halo Orbits
After completion of a resupply mission to NASA's proposed Lunar Orbital Platform - Gateway, safe disposal of the Logistics Module is required. One potential option is disposal to heliocentric space. This investigation includes an exploration of the trajectory escape dynamics from an Earth-Moon Near Rectilinear Halo Orbit (NRHO) and applies these insights to the design of a low-cost heliocentric Logistics Module disposal option. The effects of the solar gravitational perturbations are assessed in both the bicircular restricted 4-body problem and in an ephemeris force model
Taxonomic Composition and Trophic Structure of the Continental Bony Fish Assemblage from the Early Late Cretaceous of Southeastern Morocco
International audienceThe mid-Cretaceous vertebrate assemblage from south-eastern Morocco is one of the mostdiversified continental vertebrate assemblages of this time worldwide. The bony fish component(coelacanths, lungfishes and ray-finned fishes) is represented by relatively completespecimens and, mostly, by fragmentary elements scattered along 250 kilometres of outcrops.Here we revisit the bony fish assemblage by studying both isolated remains collectedduring several fieldtrips and more complete material kept in public collections. The assemblagecomprises several lungfish taxa, with the first mention of the occurrence of Arganodustiguidiensis, and possibly two mawsoniid coelacanths. A large bichir, cf. Bawitius, is recordedand corresponds to cranial elements initially referred to ‘Stromerichthys’ from coevaldeposits in Egypt. The ginglymodians were diversified with a large ‘Lepidotes’ plus twoobaichthyids and a gar. We confirm here that this gar belongs to a genus distinctive fromRecent gars, contrary to what was suggested recently. Teleosteans comprise a poorlyknown ichthyodectiform, a notopterid, a probable osteoglossomorph and a large tselfatiiform,whose cranial anatomy is detailed. The body size and trophic level for each taxon areestimated on the basis of comparison with extant closely related taxa. We plotted the averagebody size versus average trophic level for the Kem Kem assemblage, together with extantmarine and freshwater assemblages. The Kem Kem assemblage is characterized bytaxa of proportionally large body size, and by a higher average trophic level than the trophiclevel of the extant compared freshwater ecosystems, but lower than for the extant marineecosystems. These results should be regarded with caution because they rest on a reconstructedassemblage known mostly by fragmentary remains. They reinforce, however, theecological oddities already noticed for this mid-Cretaceous vertebrate ecosystem in NorthAfrica
Disposal, Deployment, and Debris in Near Rectilinear Halo Orbits
A proposed Gateway facility in a lunar Near Rectilinear Halo Orbit (NRHO) will serve as an outpost in deep space, with spacecraft periodically arriving and departing. Departing objects will include logistics modules, requiring safe disposal, cubesats, deployed to various destinations, and debris objects, whose precise paths may be unknown. Escape dynamics from NRHOs are complex; primarily influenced by the Earth and Moon within the orbit, spacecraft are significantly impacted by solar gravity upon departure. The current investigation explores the dynamics of departure from the NRHO, including the risk of debris recontact, safe heliocentric disposal, and deployment to select destinations
UTILISATION D’UN MODELE HYBRIDE BASE SUR LA RLMS ET LES RNA-PMC POUR LA PREDICTION DES PARAMETRES INDICATEURS DE LA QUALITE DES EAUX SOUTERRAINES CAS DE LA NAPPE DE SOUSS-MASSA- MAROC
This work describes a new approach to the prediction of the parameters (microbiological, physical-chemical) groundwater quality indicators in the water table of Souss-Massa Morocco. The originality of this work lies in the application of a hybrid model based on the Stepwise Multiple Linear Regression and Neural Networks Multilayer Perceptron type. During the first stage, conventional statistical models namely the Stepwise Multiple Linear Regression was applied to a database that consists of eleven vectors as input vectors of the model and three vectors as the model output vectors in order to optimize the explanatory variables. In a second step, the optimized data base in the first step was used to construct a non recurring multi-layer network, the weights of the network connections are determined using the gradient back propagation algorithm. The data used as a database (learning, testing and validation) of the hybrid model are those relating to the analysis of 52 groundwater samples collected at several stations distributed in space and in time, of the groundwater Souss-Massa Morocco. The dependent variables (to explain or predict), which are three in number, are the Electrical Conductivity EC, the amount of Fecal Coliforms CF and Organic Matter MO
Contribution of Lasergrammetry, Photogrammetry and Electrical Tomography for the Survey and 3D Representation of Caves: Case Study of the Cave of Kef El Baroud, Province of Benslimane, Morocco
The modeling of caves is constantly evolving and the classic modeling tools are giving way to new techniques that are more precise and more practical, indeed scientists are increasingly using 3D modeling to improve the representations of caves, in this study we have used lasergrammetry and photogrammetry which occupy an increasing place in the 3D representation of caves. Their simplicity favors their use for recording and modeling the parietal morphology of caves and the detailed representation of the complexity of Endokarst. As part of the geomorphological study of the Kef El Baroud Cave which is located in the province of Benslimane in Morocco, two modeling methods were carried out, it is a digital survey by lasergrammetry and by photogrammetry of the cave. and its parietal morphologies. The study was completed by a topographical survey with a DistoX rangefinder. The geophysical contribution by electrical tomography was also carried out. The 3D terrestrial laser scanning technique was performed by a LEICA RTC 345 scanner. These measurements made it possible to reconstruct the evolutionary stages of the paragenetic morphologies, and their relationships with the local geomorphology, and the structural elements. The field measurements were integrated into the morphometric analyzes of the digital models, which allowed a large number of observations.The surveys also made it possible to compare the results with those of the photogrammetry carried out by a reflex camera and a wide-angle lens with appropriate editing software.Lasergrammetry and its application have enabled us to precisely position within the point cloud all the details of the covered wall, and thus constitutes, alongside photogrammetry, an interesting means for the geomorphological study of the Caves. An electrical tomography study was coupled with the other measurements and made it possible not only to delimit the walls of the Cave according to the resistivity gradients but also to detect the very probable presence of fractured zones under the Cave which could constitute an aquifer
Le patrimoine préhistorique de la marge nord saharienne. Valorisation et cartographie des sites de plein air
International audienceThe northern Saharan margin is very rich in prehistoric vestiges of diverse passages and different human occupations during periods from the lower Palaeolithic to the Neolithic. The surface sites inventoried in the south-east of Morocco are very numerous and present a significant wealth of lithic materials belonging to different civilizations. The inventory or cartography of the surface sites of the northern margin of the Sahara allowed us to determine that the Acheulean sites are generally present on the deposits of raw material, composed mainly of sandstone and quartzite. The different media of acquisition operations for both shaping and debiting are based on Levallois and Kombewa debitage. As for the Middle or Upper Palaeolithic sites, the raw material changes with the proximity of the Cretaceous Hamadas rich in flint, and it is often exploited using the recurrent and linear Levallois debitage methods, and sometimes laminar debitage is used.La marge nord saharienne est très riche en vestiges préhistoriques témoins des différents passages et de différentes occupations humaines pendant des périodes allant du Paléolithique inférieur jusqu’au Néolithique. Les sites de surfaces inventoriés dans le sud-est marocain sont très nombreux et présentent une richesse importante en matériel lithique appartenant à des civilisations différentes. L’inventaire ou la cartographie des sites de surface de la marge nord saharienne, nous a permis de distinguer que les sites acheuléens sont en général présents sur les gîtes de matière première, composée essentiellement de grès et de quartzite. Les différentes opérations d’acquisition des supports aussi bien pour le façonnage que pour le débitage se basent sur le débitage Levallois et Kombewa. Quant aux sites du Paléolithiques moyen ou supérieur, la matière première change avec la proximité des Hamadas crétacée riche en silex, et il est souvent exploité en utilisant la méthode de débitage Levallois récurrent et linéal, et parfois le débitage laminaire est utilisé
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