425 research outputs found

    Dynamic modelling of the behaviour of the quarkiss earthen dam under seismic loads

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    The dynamic modelling of the behaviour of the Ouarkiss earthen dam under seismic loads was performed using the finite elements method (FEM), with an approach in effective stresses. The soil behaviour is described by the Mohr-Coulomb criterion. A numerical method and a procedure of analysis are presented in this work. The seismic response of an earthen dam was evaluated. Particular emphasis is placed on the calculation of stresses, displacements, deformations and interstitial overpressures recorded during the seismic solicitation. It has been shown that numerical simulation is able to highlight the fundamental aspects of the displacements and deformations processes experienced by the structure ofdam and to produce preliminary results for the evaluation of the seismic behaviour of the structure taking into account the physical non-linearity of the materials constituting the body of the dam and the effect of the rigidity of the different zones of the dam and the foundation

    (4aS,10aS)-7-Hydr­oxy-8-isopropyl-1,1,4a-trimethyl-1,2,3,4,4a,9,10,10a-octa­hydro­phenanthrene: a new diterpenoid compound

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    The new title diterpenoid compound, C20H30O, is a natural product isolated from Tetra­clinis articulata wood via chloro­form extraction. The asymmetric unit contains four mol­ecules with the same S,S configuration, deduced from the chemical synthesis. Indeed, an overlay analysis, calculated using structure-matching software, shows that the four mol­ecules can be superimposed. The central ring has a half-chair conformation, whereas the saturated ring displays a chair conformation

    Impact of the Four Quality "Training, Service, Information System and Information" on the Use of Information System in an Information-Intensive Sector

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    Today, information is crucial and the flow of information is becoming more and more numerous, so their management is delicate, hence the need to use an information system that supports all production systems, and the majority of competitive advantages is achieved through the intelligent use of these information systems.It is in this context of disrupted information that the use of information systems is necessary in organizations, as they have greatly influenced the ways of work and management. For this purpose, they allow easy access to relevant information in quantity and in real time, the rapidity of analyzing this information and the possibilities for dissemination and exchange between the partners, without forgetting the possibilities for storage and archiving in a more secure way than human intervention could.The study examines the impact of quality of training, service quality, information system quality and information quality on the use of an information system. A quantitative study is conducted to test these effects, the findings of this research are mainly comprised by three facts: (1) the use of information systems is obligatory in the context of intensive information. (2) Voluntary or mandatory use status must be specified in the analysis, (3) there is no specific antecedent to the act of use of IS in the retail secto

    Ultrasound study of Moroccan Arabic labiovelarization

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    In this survey, we have provided some acoustic and ultrasound data from two subjects to characterize a secondary articulation generally analyzed as labialization in Moroccan Arabic. Our results show that the so-called labialized consonants are rather labiovelarized. They also show that the vowel [a] adjacent to the labiovelarized consonants is velarized

    Predicting the notch band frequency of an ultra-wideband antenna using artificial neural networks

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    In this paper we propose to predict the notch frequency of an ultra-wideband (UWB) antenna which operates in the frequency band from 3.85 GHz to 12.38 GHz. The prediction of the notch frequency in order to avoid interferences between (WLAN) IEEE802.11a and HIPERLAN/2 WLAN applications and UWB technology is achieved using the artificial neural networks (ANN) technique. The developed ANN is optimized with the help of K-fold cross validation method which allows us to divide the datasets into 10 subsets in the training phase. The simulated datasets are generated by controlling high frequency structural simulator (HFSS) from MATLAB using a VB script. The performance of the ANN technique is assessed using some statistical criteria. During the training process, the mean absolute percentage error (MAPE) between the simulated and the predicted ANN notch frequencies is 0,125. A comparison between simulated, theoretical, and ANN results has been achieved during the test and validation process, good accuracy is obtained between the simulated and the ANN predictions. The proposed UWB antenna exhibits a notch band from 5.1 GHz to 6.0 GHz with a notch frequency of approximately 5.51 GHz
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