Les formations plio-quaternaires de la région de Casablanca (Maroc): aspects sédimentologique et géotechnique

The Plio-Quaternary formations of the Casablanca area consist of a sequence of cross-bedded strata. They frequently begin with a lumachelle conglomerate occasionally associated with gravels and marine calcarenite. The marine deposits are overlain by yellow and grey dune sandstones, locally oxidized at depositional horizons. These dunal calcarenites have been extensively exploited and hence their sedimentological and geotechnical parameters have been determined from numerous samples taken from the quarries in the region. The sedimentological study results show that these generally homogeneous materials consist mainly of well-graded fine to coarse carbonate sands (98%) containing both bioclasts and calcareous cements. It is clear that at the time of deposition there was little detrital material, with the marine deposits formed mainly of shell debris. Study shows that the marine deposits underwent early lithification in a shallow marine environment which then continued in a continental environment by the movement of meteoric water. The marine deposits are well cemented. They have a low degree of dissolution but quite a high degree of recrystallization, notably towards the bottom of the individual horizons. The dunal deposits which underwent lithification in a continental environment are characterized by a very low cementation, mainly at point contact, a high dissolution and a weak recrystallization. The difference in diagenesis affects both the physical and mechanical features of these Plio-Quaternary calcarenites. From a geotechnical point of view, the consolidated marine and dunal deposits have a weak to medium compressive strength (502), a very weak resistance to shocks (453. 8.?Density and percentage CaCO₃. 9.?Compression resistance and percentage CaCO₃. In view of the graph relationships, it is possible to estimate the other parameters from the determination of a single physical or mechanical feature of the calcarenite. However, the sedimentological and petrographical analyses show that the following factors can be subject to quantitative variations: (1) the carbonate content; (2) the nature of the bioclastic elements; (3) the grain size of the detrital elements; (4) the cement percentage and its grain size; and (5) the importance of dissolution and the vacuum percentage. These factors control the physical and mechanical features of the Plio-Quaternary formations of the Casablanca area. As a consequence, it is suggested that when considering the sedimentological features and physical and mechanical characteristics of the Plio-Quaternary formations of the Casablanca area, the particular deposits must first be categorized into one of the four following facies: lumachelle; marine calcarenite; yellowish dunal calcarenite; or grey dunal calcarenite.     

First Principle Calculations and Monte Carlo Simulations Investigation of Structural,Electronic, Magnetic,Elastic and Thermoelectric Properties of Antiperovskites $$Mn_3ZnX (\mathrm{X}= \mathrm{C, \ N})$$ M n 3 Z n X ( X = C,N )

Journal of Superconductivity and Novel Magnetism - The structural, electronic, magnetic elastic and thermoelectric properties of $$Mn_3ZnX$$ (X = N,C) have been investigated in the framework of...     

Soft Computing Based Pattern Classifiers for the Obstacle Avoidance Behavior of Intelligent Autonomous Vehicles (IAV)

To ensure more autonomy and intelligence with real-time processing capabilities for the obstacle avoidance behavior of Intelligent Autonomous Vehicles (IAV), the use of soft computing is necessary to bring this behavior near to that of humans in the recognition, learning, adaptation, generalization, reasoning and decision-making, and action. In this paper, pattern classifiers of spatial obstacle avoidance situations using Neural Networks (NN), Fuzzy Logic (FL), Genetic Algorithms (GA) and Adaptive Resonance Theory (ART) individually or in combination are suggested. These classifiers are based on supervised learning and adaptation paradigms as Gradient Back-Propagation (GBP), FL, GA and Simplified Fuzzy ArtMap (SFAM) resulting in NN/GBP and FL as Intelligent Systems (IS) and in NN/GA, NN/GA-GBP, NN-FL/GBP and NN-FL-ART/SFAM as Hybrid Intelligent Systems (HIS). Afterwards, a synthesis of the suggested pattern classifiers is presented where their results and performances are discussed as well as the Field Programmable Gate Array (FPGA) architectures, characterized by their high flexibility and compactness, for their implementation.     

Modelling of damage and failure of glass/epoxy composite plates subject to impact fatigue

An investigation has been carried out to study the impact fatigue damage of glass/epoxy laminated composites. Accumulation of damage, such as matrix cracking, delamination and fibre breakage, with repeated impact of the composite material may reduce the overall stiffness. These damage modes have been combined in a very complicated way to describe damage growth and fracture. A model is proposed for characterising the damage as a function of the normalised impact number. The scalar variable D, which characterises the material damage, is written as a function of the life duration β, using a modified form of the Mankowsky empirical law [Int J Solids Struct 32(11) (1995) 1607]. The macroscopic failure mode and the internal damage in laminated specimens of glass/epoxy as a consequence of impact fatigue are analysed at different levels of incident impact energy. The impact fatigue tests have been conducted on an apparatus built in our laboratory.     

The case of extreme hydrologic drought downstream from reservoirs in Quebec (Canada): The intermittent flow

Intermittent flow is a hydrological phenomenon observed at all latitudes. This phenomenon is characterized by a complete or partial interruption of flow in time and/or space in channels. In Quebec, even though the climate is humid, intermittent flow occurs downstream from headwater reservoirs. These reservoirs store water during spring and summer (from April to September) and release it in winter to supply hydroelectric power plants located downstream. During the water storage period, intermittent flow is common (discharges falling to <1 L/s/km²). The goal of the study is to analyse the characteristics (magnitude, frequency, and duration) of this flow downstream from 3 reservoirs built in the Saint‐Maurice River watershed, during the period from 1930 to 2010. Downstream, the contribution (magnitude) of intermittent flow to total altered flow is less than 2%. Intermittent flow frequency ranges from 24 to 65 days per year downstream from the 3 reservoirs. As far as duration is concerned, intermittent flow persists on average from 40 to 128 consecutive days. Canonical correlation analysis revealed that the frequency of intermittent flow is correlated with the North Atlantic Oscillation and its magnitude and negatively correlated with the Southern Oscillation.