Dimensionnement hydrologique des retenues collinaires en Algérie

Dans les pays semi-arides et méditerranéens, la production agricole peut être intensifiée par la création de nombreuses retenues collinaires. Une série de manuels a été réalisée en Algérie afin de permettre la construction rapide, et suivant des règles homogènes, de centaines de retenues collinaires. Il a été ainsi élaboré en particulier un manuel pour le dimensionnement hydrologique des retenues dont les principes sont exposés dans le présent article. Des abaques normalisés présentant en compte les apports moyens des bassins versants ont été préparés suivant une variante généralisée du modèle MORAN, en utilisant les chroniques d'observations des stations hydrométriques des diverses unités géographiques. Il a été construit, pour leur mise en application, des cartes des isolignes relatives aux apports annuels moyens et aux apports annuels de fréquence 80% au dépassement. (Résumé d'auteur

Barriers to ISO 9001 Implementation in Moroccan Organizations: Empirical Study

Purpose: The purpose of this paper is to explore obstacles to ISO 9001 quality management system implementation in Moroccan firms. Design/methodology/approach: A questionnaire survey has been conducted among a heterogeneous sample of 200 organizations, operating in different sectors in Morocco, yielding a response rate of 57.5%. The authors have studied barriers to quality initiatives in general and obstacles to QMS implementation in particular through an extensive literature review. Questions related to profiles of respondents, reasons of seeking certification, external consultancy and barriers to ISO 9001 implementation experienced by surveyed organizations. For the purpose of this study, authors considered three categories of quality inhibiting factors: organizational, technical and costs related barriers. Findings: Results indicate that surveyed companies sought ISO 9001 certification mainly for marketing reasons and experienced many difficulties during the implementation process. Barriers reported by respondents were mostly organizational. Resistance to change headed the list according to participants’ opinion. Also, findings highlighted the prominence of bureaucracy and poor interdependence between departments in organizations. Lack of communication, poor top management commitment and insufficient trainings were also ascertained to be obstacles to QMS implementation in Morocco. Originality/value: Earlier studies were led by different researchers in different countries about barriers to quality initiatives in general and to ISO 9001 implementation in particular. Few of those studies were conducted in Arab speaking countries but no research has been carried in Morocco. This study on obstacles to QMS implementation in Morocco will help in completing the jigsaw of difficulties faced by organizations worldwide when preparing to ISO 9001 certification. Research limitations/implications: This research is limited by the geographic context of the study Morocco, although results can be extrapolated to Arab speaking countries in general. Practical implications: The findings of this paper provide Moroccan managers with a practical understanding of the factors that are likely to obstruct ISO 9001 QMS implementation. Managers should overcome these barriers to achieve a successful implementation and higher QMS performance.Peer Reviewe

Une contribution expérimentale à l'étude de l'érosion d'une digue par submersion et son analyse

Dans cet article, on décrit un essai réalisé sous conditions contrôlées en laboratoire concernant l'initiation et le démarrage de la rupture par submersion d'une digue de revanche homogène et en moraine, un matériel utilisé dans les ouvrages réels, de granulométrie étendue et sans cohésion.Les résultats obtenus sur cette digue expérimentale ont montré que le mécanisme de formation et d'érosion de brèche est très différent du mécanisme global et moyen de développement et de progression de la brèche adopté dans les modèles courants de calcul des ruptures de barrages. L'essai souligne l'importance de la turbulence et des pertes de charge locales dans certaines zones spécifiques de l'écoulement et met en évidence le rôle de l'instabilité des parois latérales de la brèche dont la base est sapée continuellement.L'essai a été stoppé à un moment précis, soit lorsque l'accroissement rapide du débit de rupture était confirmé, afin de préserver les caractéristiques géométriques précises de la brèche en cours de formation. Les données ainsi recueillies sur la rupture de la digue d'essai sont utiles à tout développeur voulant valider sa compréhension physique de l'érosion de brèche ou un outil de calcul visant à reproduire ce mécanisme. Le texte présente aussi une analyse comparative effectuée par un outil informatique de prévision, BRECHE, et la confrontation des résultats produits selon cinq méthodes publiées durant les dernières décennies et reconnues.Une appréciation des résultats obtenus par prévision et des nombreuses données issues de l'essai réalisé sur le modèle en laboratoire est présentée et discutée.It has been recognized for several decades that the reliability of forecasts for flooding downstream from a dam failure depends not only on the local topography but also on the failure mode of the dam, specifically on the breach outflow hydrograph. It is therefore of primary importance that the mechanism of formation of the breach is anticipated with an acceptable degree of accuracy. Several approaches to model this phenomenon have been reported in the literature, but the results from these models do not appear to be reliable when the predicted values are compared with those deduced from observations carried out on real or simulated dam failures. Each failure of a dam generates a particular form of hydrograph that will have a specific impact on the affected population. The most frequent cause of failure of earthfill and rockfill dams is by overtopping of the crest, although in rockfill dams initial piping failure followed by partial collapse of the crest resulting in breach initiation has been observed. Once initiation of a breach has occurred, continuous development until complete failure occurs is virtually assured if sufficient energy from the reservoir volume is available to sustain the breaching process. For this reason, breach formation is recognized as one of the essential factors in the modeling of a dambreak.To anticipate the real hazard from dam overtopping, a predictive model for breach initiation and development would be extremely useful. Currently, the majority of dam safety studies assume a standard scenario for the breach formation, development and final failure based on some norms established as a result of regression analyses on some actual failures. Modeling of the breach and therefore prediction of the outflow hydrograph do not take into account specific local data on the construction techniques and soil properties, mainly because currently available methods that attempt to incorporate these factors still do not provide reliable results. To contribute to the understanding of the mechanism of breach formation and to determine the details of the process, a test of erosion failure was performed and documented at the Hydrodynamics Laboratory of the École Polytechnique de Montreal. This test, coupled with the subsequent development of a numerical model incorporating the interactions of the hydraulics-erosion process, has formed the basis of a doctoral dissertation, the principal objective being to reproduce as accurately as possible the mechanisms involved in the formation of a breach (ZERROUK, 2004; ZERROUK et MARCHE, 2004).This paper describes a test carried out under controlled laboratory conditions on a homogeneous dam composed of moraine, a material used in the construction of real dams with an extended non-cohesive granulometry. The test simulated the initiation and the start of the failure by dike overtopping known as a " fuse plug " i.e. a dike that, during an event of exceptional rain or extreme inflow, would be used to limit the volume retained in the reservoir. The test, carried out on a laboratory scale but extrapolated to prototype dimensions without similarity considerations, nevertheless allowed identification of the various mechanisms that intervene in the breaching process.The results obtained on this experimental dike showed that the mechanism of formation and erosion of a breach is quite different from the mechanisms assumed in standard methods of computation of the rupture. Current models give undue weight to a single failure mechanism, independent of lateral slope instability, surface erosion or shear stress energy. The laboratory test however indicated the importance of turbulence and erosion in certain specific zones of the flow and highlighted the role of sidewall instability at the base of the breach, which erodes continuously leads to lateral instability.Currently, engineers attempt to predict breach outflow based on the formation of the breach using physical properties of the component material such as the angle of friction, the slope angle of the breach channel and a factor for the rate of growth of breach width. The present authors recognize major deficiencies in this approach such as the use of assumptions for the breach geometry, the progression of the rupture, the use of material transport expressions based only on shear stress considerations (FREAD, 1984c) or the use of empirical 'adjustment' factors influencing the erosion of compacted cohesive soils (SINGH et SCARLATOS, 1989). The data acquired from the experimental dike were used in a data-processing tool for comparative analysis called BREACH, in which five methods for predicting the formation of a breach by overtopping of dams composed of granular material were programmed (ZERROUK, 2004; ZERROUK et MARCHE, 2001). Starting with the same data obtained from the laboratory test, each of the models was applied and the results discussed with respect to whether the principal factor for breach evolution that is presumed predominant for the breaching process in the model, corresponds in fact to the mechanism observed during the test.The analysis highlights the factors, ignored in the current models, which may in fact explain the mediocre results obtained for the predictions. It indicates that the characterization of the breach geometry is the major uncertainty in these models, which result in peak outflows and corresponding times never being simultaneously predicted correctly

Citrulline: from metabolism to therapeutic use.: citrulline: metabolism and therapeutic

International audienceCitrulline possesses a highly specific metabolism that bypasses splanchnic extraction because it is not used by the intestine or taken up by the liver. The administration of citrulline may be used to deliver available nitrogen for protein homeostasis in peripheral tissues and as an arginine precursor synthesized de novo in the kidneys and endothelial and immune cells. Fresh research has shown that citrulline is efficiently transported across the intestinal luminal membrane by a set of transporters belonging to the B⁰,⁺, L, and b⁰,⁺ systems. Several pharmacokinetic studies have confirmed that citrulline is efficiently absorbed when administered orally. Oral citrulline could be used to deliver arginine to the systemic circulation or as a protein anabolic agent in specific clinical situations, because recent data have suggested that citrulline, although not a component of proteins, stimulates protein synthesis in skeletal muscle through the mammalian target of rapamycin signaling pathway. Hence, citrulline could play a pivotal role in maintaining protein homeostasis and is a promising pharmaconutrient in nutritional support strategies for malnourished patients, especially in aging and sarcopenia

Hadron calorimeter with MAPD readout in the NA61/SHINE experiment

The modular hadron calorimeter with micro-pixel avalanche photodiodes readout for the NA61/SHINE experiment at the CERN SPS is presented. The calorimeter consists of 44 independent modules with lead-scintillator sandwich structure. The light from the scintillator tiles is captured by and transported with WLS-fibers embedded in scintillator grooves. The construction provides a longitudinal segmentation of the module in 10 sections with independent MAPD readout. MAPDs with pixel density of $~10^{4}$/mm$^2$ ensure good linearity of calorimeter response in a wide dynamical range. The performance of the calorimeter prototype in a beam test is reported

Network Intrusion Detection System for Denial-of-Service attack detection in 5G

The number of connected devices in the network continues to increase year by year, specially with the introduction of fifth-generation (5G) technology, which offers higher capacity to accommodate the growing demand. However, these devices, such as Internet of Things (IoT), are vulnerable to Denial of Service (DoS) attacks if they are not properly secured. A DoS attack inundates a network or device with excessive traffic, overwhelming it until it is inaccessible to legitimate users. This vulnerability poses significant risks to critical services such as healthcare, energy, and transportation. This thesis addresses the challenge of detecting DoS attacks in 5G networks by designing and developing an Intrusion Detection System (IDS) based on Deep Learning (DL). The proposed IDS monitors network traffic in real-time to identify DoS patterns and alerts administrators when potential attacks are detected. The designed IDS is composed of two neural network models: the ADC model, which classifies benign network traffic flows from flows containing DoS patterns, and the DoSC model, which categorizes the specific type of DoS attack. These ML models are trained using the Federated Learning (FL) paradigm, which involves three clients, each utilizing a portion of data from a public 5G network traffic dataset. This approach enables the IDS to learn from diverse data sources without compromising data privacy. The IDS models were evaluated on unseen data, achieving an accuracy of 100%, which demonstrates the high capability of the IDS to detect DoS patterns in network flows. The developed IDS was deployed in a simulated environment, where it receives network traffic flows, analyses the network to alert administrators upon detection, and provides an interface for monitoring the detected DoS attack flows

Improving properties of modified clay with cement containing random chicken feather fibers

Over the past decades, the poultry meat processing industry’s growth has generated a huge amount of feather “waste”. This waste has given rise to a number of environmental concerns and had a low value-being when used in many industrial applications. Promoting the use of sustainable materials is now a pole of interest in engineering construction. Aiming to recover this waste in enhancing the properties of problematic soils, an experimental study is conducted using these materials. An earth material named Zebabdja clay is treated by the cement to improve its properties. The inclusion of waste byproducts such as chicken feather fibers would improve the characteristics of the soil with low load bearing capacity. The present work attempts to valorize this kind of natural fiber in the field of building and solve an environmental problem using local materials. The control parameters evaluated herein include cement content (6%, 8%, 10% et 12%) and chicken feather fibers contents (1%, 2% et 3%). The unconfined compressive and direct shear tests were measured at different curing times. The results found show that 10% is the needed amount of cement to be used in order to stabilize the clayey soil treated. An increase in chicken feather fibers up to 2% indicates an improvement of the mechanical performances of the clayey soil, which may constitute a very interesting engineering solution for the weak soil

Improving properties of modified clay with cement containing random chicken feather fibers

Over the past decades, the poultry meat processing industry’s growth has generated a huge amount of feather “waste”. This waste has given rise to a number of environmental concerns and had a low value-being when used in many industrial applications. Promoting the use of sustainable materials is now a pole of interest in engineering construction. Aiming to recover this waste in enhancing the properties of problematic soils, an experimental study is conducted using these materials. An earth material named Zebabdja clay is treated by the cement to improve its properties. The inclusion of waste byproducts such as chicken feather fibers would improve the characteristics of the soil with low load bearing capacity. The present work attempts to valorize this kind of natural fiber in the field of building and solve an environmental problem using local materials. The control parameters evaluated herein include cement content (6%, 8%, 10% et 12%) and chicken feather fibers contents (1%, 2% et 3%). The unconfined compressive and direct shear tests were measured at different curing times. The results found show that 10% is the needed amount of cement to be used in order to stabilize the clayey soil treated. An increase in chicken feather fibers up to 2% indicates an improvement of the mechanical performances of the clayey soil, which may constitute a very interesting engineering solution for the weak soil

Recognition of coordinate in the scanned maps for automated Georeferencing by Bezier curves and supervised learning

In this project, we can see how to add georeferencing to scanned maps and aerial photos so that their value can be multiplied through association with other data. Where good georeferenced control layers can be found, the process of georeferencing an image is surprisingly easy