Ressources hydriques en Algérie du Nord

En Algérie, l'eau revêt un caractère stratégique du fait de sa rareté et d'un cycle naturellement perturbé et déséquilibré. Qu'il s'agisse de l'eau souterraine ou de l'eau de surface, les ressources sont limitées et, compte tenu des problèmes démographiques et de l'occupation de l'espace (sachant que près de 60% de la population algérienne sont concentrés dans la frange septentrionale du territoire qui ne représente que le dixième de la surface totale du pays), d'importants efforts sont nécessaires en matière d'urbanisation intégrée et de gestion rigoureuse dans l'exploitation des réserves, si on veut atteindre la satisfaction des besoins à l'horizon 2010. S'y ajoutent des problèmes de faible mobilisation et de mauvais recyclage par manque de maîtrise des stations d'épuration et l'envasement des retenues.Les 11 bassins versants exoréiques de l'Algérie du Nord couvrant une surface de 130 000 km2 présentent des potentialités en eaux de surface de 11.109 m3 dont seulement 2,13.109 sont mobilisés par les 98 barrages en fonctionnement en 1995. Les besoins estimés à l'horizon 2010 évalués à 9,384. 109 m3 se décomposent en 1,524.109 m3 pour l'eau potable (AEP), 0,23.109 m3 pour l'industrie (AEI) et 7,63.109 m3 pour l'agriculture (AEA) (tableau 6). Sachant que les réserves en eaux souterraines sont évaluées à 1,25.109 m3, le renforcement de la mobilisation des eaux de surface par 3,834. 109 m3 et des eaux souterraines par le captage de 0,33.109 m3 supplémentaires constituent la projection faite en 1995 pour l'horizon 2010 par les différentes institutions publiques intervenant dans la mobilisation et la gestion des ressources en eaux. Cet objectif est déjà fortement entamé en 2002 car fixé dans un contexte de cloisonnement des différentes structures (Hydraulique et Agriculture) et de difficile circulation de l'information entre elles. Il surévalue les capacités de réalisations des barrages, les surfaces à mettre en valeur dans le cadre du programme de développement agricole ainsi que les dotation par habitant en matière d'eau potable. Cette situation constitue un facteur aggravant la difficulté d'une appréhension correcte aussi bien des besoins que des différentes projections sur l'avenir. Les données présentées dans cette synthèse montrent qu'il est désormais impératif que l'aménagement du territoire tienne compte des quantités disponibles afin de rationaliser l'utilisation, la protection de la qualité et la récupération par le recyclage.La qualité chimique des eaux de l'Algérie du Nord est appréciée par les teneurs en nitrates et en chlorures des aquifères côtiers. Cependant, le développement économique et social conduit à une dégradation rapide de cette qualité des eaux, ce qui incite lourdement à œuvrer pour un meilleur recyclage et une meilleur protection des ressources. A défaut, la sanction serait la non satisfaction des besoins en eaux potable, d'irrigation et industrielle. Malheureusement, il semble que l'écart entre disponibilité et besoins soit difficile à réduire. Le but de cet article est de tenter une revue des causes du manque d'eau et des facteurs aggravants.In Algeria, water has a strategic place in economic development, because of its scarcity and a perturbed, non-equilibrated natural cycle. Because of the limited water resources, and the need to meet the demands for the desired quantity and quality of water by the year 2010, planners must develop reasonable alternatives that take into account multiple purposes and objectives. In addition to the growing demography, 60% of the population resides in the northern range of Algeria, which represents one tenth of the total area of the country. Furthermore, inadequate water treatment due to a lack of appropriate technology, siltation of existing dams and limited capacities for water storage hamper the decision-making process.The projected data for year 2010 show structural difficulties and organizational inadequacies that are linked to the multiple operating structures in charge of collecting and conveying the information. The other major difficulty is based on the quality of the information (e.g., empirical methods and a lack of data). For example, the evaporation rate is estimated by the traditional method of a Colorado pan in which the data are mostly discontinuous. The reservoir silt load is evaluated by irregular bathymetric measurements and the results are extrapolated over a year, sometimes from one year to the next. The volume of water losses during water transport and distribution is evaluated for only a very small portion of the network and is then generalized to the entire drinking water and irrigation system.The eleven watersheds of northern Algeria encompass an area of about 130,000 km2 and offer a surface water potential of approximately 11×109 cubic meters (m3) in which only 2.13×109 m3 were collected by 98 functional dams in 1995. According to the forecasts made in 1995, the creation of new reservoirs (17 dams are actually under construction, 25 are about to start construction, and 810 sites for small reservoirs are in the study phase) will increase the mobilized volume of water to about 5.89×109 m3. The silt load for 1995 as estimated by the National Dams Agency (ANB) for all the operational reservoirs corresponded to about 0.02×109 m3. Watershed erosion and the rapid degradation of the forest cover will raise this silt load to 0.482×109 m3. This situation is very alarming for the water resources and consequently in December 2001, the exploitation of major dams (Keddara, Fergoug, Oued Fodda, Ghrib, Beni Amrane, Ksob, Foum el Gherza, Foum el Gueiss) was temporary interrupted. Operations at the Ain Dalia and Hamman Grouz reservoirs were also interrupted in October 2002 due to silt load problems.The water losses from the distribution network, which were estimated around 1.193×109 m3 in 1995, will be reduced to about 0.532×109 m3 in the year 2010 by special renovation programs. The volume of water lost by evaporation represented 0.427×109 m3 in 1995 and will double for year 2010 to reach 0.883×109 m3, according to the ANB.In 1995, groundwater was pumped at a volume of about 0.849×109 m3 from an estimated total reserve of 1.256×109 m3. The urgent program of installing an additional 2000 wells will raise the extracted volume to 1.180×109 m3 by the year 2010. In the northern portion of the country, the water needs will evolve in the following manner : · from 0.791×109 to 1.524×109 m3 per year for drinking water ; · from 1.216×109 to 7.630×109 m3 per year for agricultural needs ; · from 0.120×109 to 0.230×109 m3 per year for industry.It seems clear that the forecast made in 1995 is infeasible and unrealistic. This prediction overevaluates the financial and technical capacities to carry out all the planned projects and also overestimates the land surface for the agricultural development program. The state of water resources and their distribution for the year 2002 already indicate depletion. Accordingly, the following incentive plans were proposed : · Urgent programs for providing potable drinking water from treated seawater for coastal big cities (Algers, Oran, Arzew, and Annaba). This alternative has been implemented starting September 2002 for Annaba and Arzew. · Encouraging and developing agricultural crops that consume less water and encouraging use of modern techniques for irrigation (drop irrigation). · Activating the construction of the 800 planned watershed reservoirs. · Implementing a program for treating and recycling waste waters. The groundwater quality analysis in the northern portion of Algeria, based on the nitrate and chloride concentrations, led to the following conclusion : · Increasing nitrate concentrations for groundwater samples (up to 175 mg×L-1 for Chlef, 200mg×L-1 for Sidi Bel Abbes, and values exceeding the permissible level of 45 mg×L-1 for over half of the sampling points throughout the Mitidja). · The dilution effect during flood events does not overcome the contamination of groundwater by the nitrates. · Most of the coastal aquifers are contaminated by seawater intrusion. The chloride concentration values are about 3,650 mg×L-1 for Algiers region (Mazafran) and sometimes exceed 4,000 mg×L-1 in the eastern portion of the country (Bourchaid, Kissir). · Water samples from dams and large reservoirs were not contaminated by nitrates because of the absence of agricultural activities in the watershed.The degraded water quality and its scarcity complicate the problem of water supply that is already critical in the region.In conclusion, the gap between water needs and the available water resource is very difficult to close. The goal of this article is to review some of the effects of water shortage and its components. The present article emphasizes the need to implement a change in the decision-making process for controlling and managing water. Improved management of water supplies must not only take into account the available water but also has to optimize and rationalize its use. An urgent planning program should also be developed for treating and recycling waste water and for protecting the environment

Steady and Unsteady compressible Reduced-Order Models of a Zero-Net Mass-Flux Synthetic Jet Actuator

International audienceIn the framework of an optimization study of a Zero-Net-Mass-Flux fluidic, synthetic jet actuator, based on a multi-objective optimization formulation, the consideration of optimization parameters such as the actuator location and the outlet design implies a re-meshing procedure that adds complexity. It is still the case even if the actuator is modeled with simple boundary conditions at the jet orifice exit since, locally, the re-mesh is still required. This strongly impacts the global computational cost, in particular if the considered geometry is complex. In a previous study, we proposed an alternative method to model Zero-Net Mass Flux synthetic jet actuators through the implementation of volumetric reduced-order models (ROM) as additional source terms. The previous reduced-order model consisted in a simplified ROM model where a constant-in-space momentum quantity was imposed in the ROM formulation and the compressible effects were neglected. In this paper, we propose to extend the previous work in an attempt to apply this ROM strategy to higher Mach number flows, where compressibility effects at the outlet of the pulsed jets can no more be neglected, while improving the early interaction of the pulsed jet with the surrounding flow by considering the starting jet influence when the actuators are operated in a pulsed manner

Thermal Characterisation of composite walls made from waste Materials

Sustainable development has been an ever-growing global concern over the years, especially with respect to the environment. The construction sector is a major cause for concern due to the devastating effects traditional building materials, manufacturing processes and procurement, have on the environment. Inadequate housing in developing countries is also another major sustainable development challenge. These illustrate the cogent need for developing new methods of delivering sustainable housing that can be accessible to low-income communities who have little or no access to finances. This study compares the thermal performance of low-cost building components made from incorporating waste materials in cement blocks, thereby reducing the quantity of new materials needed. Three samples (wall panels) were made. Each panel was 330mm × 330mm × 240mm and incorporated 25 × 500ml plastic bottles laid horizontally in rows. A sand and cement mixture (ratio 1:3) was used as a binder and filled the gaps between the plastic bottles. The bottles in the first sample were filled with sand, those in the second were filled with water, and those in the third with used plastic carrier bags. A guarded hot box was developed to experimentally measure the U-values of the samples following the BS EN ISO 8990 standards. It was observed that the samples with the plastic bags had the lowest U-value, about 60% lower than samples with sand. The results show a promising potential for low-grade plastic waste to be used as a means of improving the thermal performance of low-cost buildings

Reconstruction. Introduction

The theme of the 2017 SAES conference “(Re)construction(s)” is particularly pertinent in the area of colonial and postcolonial studies, for it captures one of its underlying preoccupations. It suggests that the ultimate purpose of postcolonial deconstruction – which represents a first step toward a transformation of critical thought that aims at overcoming Eurocentric approaches to space, place, people, and nations – is reconstruction. By incorporating other voices, postcolonial deconstructio..

Beate Neumeier and Kay Schaffer, eds., Decolonizing the Landscape: Indigenous Cultures in Australia

Beate Neumeier and Kay Schaffer’s edited book, Decolonizing Landscape: Indigenous Cultures in Australia, examines the violence of Australia’s colonial past to engage in an intercultural dialogue and call for a renewed ethical response. The multi-disciplinary character of the topic is clearly reflected in this volume which brings together 15 innovative essays that combine philosophical, ethnographic, psychoanalytical, postmodern, and postcolonial approaches. In their introduction, Neumeier and..

Fluid solid interaction simulation of CFRP shell structure

Accepted manuscript version. Published version available at http://nonlinearstudies.com/index.php/mesa/article/view/1532.This work attempts to model the dynamic behavior of Carbon Fiber Reinforced Polymer (CFRP) shell structure subjected to water shock wave to improve the results presented in the study by Khawaja et al., 2014. In the previous study, the real physical problem was simplified by decoupling the fluid and the structural phenomena, applying the recorded experimental fluid pressure load to the CFRP shell structure. The current study involves not only structure modeling, as given in the earlier study, but also fluid behavior using the Arbitrary Lagrangian-Eulerian (ALE) method. The focus of this study is to highlight the difference in structural response between uncoupled and coupled Fluid Structure Interaction (FSI) numerical solution, and also to validate the ability of the FSI numerical simulation to solve complex problems, involving the generation and the propagation of water shock waves and their impact on the composite shell structures, using both multi-material ALE (MM-ALE) methods and advanced non-linear Fluid Structure Interaction (FSI) strong coupling algorithms. Results obtained from experiments are compared with numerical simulations using the LS-DYNA (R) software. The results are found to be in good agreement with the experimental data and are improved by considering the coupling effects, as the mass of the water acts as a viscous damper and reduces the high-frequency oscillations in the structural response

Doing challenging research studies in a patient centred way: qualitative study to inform a randomised controlled trial in the paediatric emergency care setting

Objective: To inform the design of a randomised controlled trial (called EcLiPSE) to improve the treatment of children with convulsive status epilepticus (CSE). EcLiPSE requires the use of a controversial deferred consent process. Design: Qualitative interview and focus group study. Setting: 8 UK support groups for parents of children who have chronic or acute health conditions and experience of paediatric emergency care. Participants: 17 parents, of whom 11 participated in telephone interviews (10 mothers, 1 father) and 6 in a focus group (5 mothers, 1 father). 6 parents (35%) were bereaved and 7 (41%) had children who had experienced seizures, including CSE. Results: Most parents had not heard of deferred consent, yet they supported its use to enable the progress of emergency care research providing a child's safety was not compromised by the research. Parents were reassured by tailored explanation, which focused their attention on aspects of EcLiPSE that addressed their priorities and concerns. These aspects included the safety of the interventions under investigation and how both EcLiPSE interventions are used in routine clinical practice. Parents made recommendations about the appropriate timing of a recruitment discussion, the need to individualise approaches to recruiting bereaved parents and the use of clear written information. Conclusions: Our study provided information to help ensure that a challenging trial was patient centred in its design. We will use our findings to help EcLiPSE practitioners to: discuss potentially threatening trial safety information with parents, use open-ended questions and prompts to identify their priorities and concerns and clarify related aspects of written trial information to assist understanding and decision-making

Volumetric Reduced-Order Models of Zero-Net Mass-Flux Actuator

In the framework of an optimization study based on a multi-objective optimization formula- tion, the consideration of optimization parameters such as the actuator location and the outlet design implies a re-meshing procedure that add complexity (even if the actuator is modeled with simple boundary conditions at the jet orifice exit since, locally, the re-mesh is still required). This strongly impacts the global computational cost, in particular, if the considered geometry is complex. In this paper, we propose an alternative method to model ZNMF synthetic jet actuators through the implementation of volumetric reduced-order models of ZNMF synthetic jet actuators as additional source terms, in the form of body forces on given local control volumes corresponding to the actual locations of the actuators. This approach is promising as it allows to skip re-meshing procedures (velocity inlet boundaries or full synthetic jet actuator modeling) by directly plugging the volumetric source terms at appropriate locations and, consequently, save considerable computational time during the optimization process

Steady and Unsteady compressible Reduced-Order Models of a Zero-Net Mass-Flux Synthetic Jet Actuator

In the framework of an optimization study of a Zero-Net-Mass-Flux fluidic, synthetic jet actuator, based on a multi-objective optimization formulation, the consideration of optimization parameters such as the actuator location and the outlet design implies a re-meshing procedure that adds complexity. It is still the case even if the actuator is modeled with simple boundary conditions at the jet orifice exit since, locally, the re-mesh is still required. This strongly impacts the global computational cost, in particular if the considered geometry is complex. In a previous study, we proposed an alternative method to model Zero-Net Mass Flux synthetic jet actuators through the implementation of volumetric reduced-order models (ROM) as additional source terms. The previous reduced-order model consisted in a simplified ROM model where a constant-in-space momentum quantity was imposed in the ROM formulation and the compressible effects were neglected. In this paper, we propose to extend the previous work in an attempt to apply this ROM strategy to higher Mach number flows, where compressibility effects at the outlet of the pulsed jets can no more be neglected, while improving the early interaction of the pulsed jet with the surrounding flow by considering the starting jet influence when the actuators are operated in a pulsed manner

Employing the behavioral integration of the top management team (TMTBI) in enhancing the strategic flexibility of organizations, "an applied study on a sample of top management employees in Algerian public banks

تهدف هذه الدراسة إلى تحديد تأثير أبعاد التكامل السلوكي لفريق الإدارة العليا في أبعاد المرونة الاستراتيجية مجتمعة. ولدراسة واقع هذا تأثير تم اختيار عينة عشوائية مكونة من 87 إطار من إطارات الإدارة العليا موزعة على مجموعة من البنوك العمومية الجزائرية  في كل من ولاية البيض، تيارت والأغواط ، بالاعتماد على الاستبيان كأداة لجمع البيانات و معالجتها بمجموعة من الأساليب الإحصائية المناسبة باستعمال البرنامج الإحصائي Spssv26 ، تم التوصل إلى وجود أثر قوي ذو دلالة إحصائية لأبعاد التكامل السلوكي لفريق الإدارة العليا في تعزيز المرونة الاستراتيجية في البنوك العمومية الجزائرية ، وبالتالي توصي الدراسة الى وجوب تحديث القطاع البنكي وباقي قطاعات الاقتصادية لفلسفتهم لموائمة المواضيع الإدارية المعاصرة خصوصا ما تعلق بالسلوك التنظيمي .This study aims to determine the effect of the dimensions of behavioral integration of the top management team on the dimensions of strategic flexibility combined. To study the reality of this effect, a random sample consisting of 87 executives of top management distributed to a group of Algerian public banks in each of Province of Al-Bayadh, Tiaret and Laghouat  was selected, relying on the questionnaire as a tool for data collection and processing with a set of appropriate statistical methods using the Spssv26, it was found that there is a strong statistically significant effect of the dimensions of behavioral integration of the top  management team in enhancing strategic flexibility in Algerian public banks, and therefore the study recommends that the banking sector should update its philosophy to harmonize contemporary administrative issues, especially with regard to organizational behavior