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International audience; Low phosphorus (P) availability is a major constraint for chickpea production. Consequently, P-efficient genotypes can improve productivity under conditions where the higher application of P is not economical. This study was conducted to characterise four chickpea genotypes for nutrient uptake and use efficiency under low-P conditions over two growing seasons. At flowering stage, plants were harvested and analysed for their nodulation, growth, P content and yield. Results indicate that low P availability significantly limited plant growth, nodulation and yield for all genotypes with the greatest effect on for Flip 84-92C and Flip 01-29C. The genotypes Flip 90-13C and ILC 32-79 showed the highest P uptake and use efficiency. The genotypes with high nutrient uptake had better efficiency in use of rhizobial symbiosis. It is concluded that nutrient uptake and use efficiency may be an important functional trait that may contribute to the selection of cultivars able to produce high quality seeds and efficiently fix nitrogen under conditions of low soil P.

International audience; Intercropping ensures multiple benefits like enhancement of yield, environmental security, production sustainability, and greater ecosystem services. In order to better understand how mixed crop cultures mitigate stressful conditions, this study aims to highlight the beneficial effect of the intercropping legume-cereal in enhancing nutrient uptake for plant growth and productivity in low phosphorus (P) soils. To address this question, faba bean (Vicia faba L. cv. Sidi Aich) and barley (Hordeum vulgare L. cv. Rihane 3) were grown as sole- and inter-crops over two growing seasons in 2017 and 2018 in a northern Algerian agro-ecosystem with a semiarid Mediterranean climate. The results showed that the plant growth and nodulation were significantly increased by 18% and 32%, respectively, for intercropping than for sole cropping and so more in 2018 compared to 2017. Moreover, grain yield and resource use efficiency (N and P) were significantly improved, as indicated by higher land equivalent ratio (LER > 1) in intercropping over sole cropping treatments. Also, the P and N concentrations measured in the rhizosphere were increased compared to bulk soil and even more so in the rhizosphere of intercropped species over two seasons. Our findings suggest that intercropping cereals with legumes may achieve high crop productivity and land use efficiency at reduced input levels.

International audience; The capacity of legumes to fix atmospheric dinitrogen in partnership with rhizobia provides an input-saving and resource-conserving alternative, thereby reducing the need for chemical fertilizers while enhancing overall crop productivity. However, low soil nutrient availability, notably phosphorus (P), is among the most nutrient limitations for legumes, since legume nodules responsible for N-2 fixation have a high P requirement. In order to explore the genetic variability for P uptake and use efficiency in low-P availability in soils, three faba bean genotypes namely Sidi Aich, Castel and Diva were studied in two field sites (S1 and S2) over two growing seasons 2018 and 2019. At flowering stage, plants were harvested and analyzed for their nodulation, growth, P content and yield. Results indicate that low-P availability in the soil of S1 significantly limited plant growth, nodulation, and grain yield for all genotypes though with highest extent for Diva and Castel. We found a significant correlation between nodule growth of all genotypes and Olsen-P content in the rhizosphere soil during two growing seasons. It is concluded that the genotypes selected for their P uptake and use efficiency had a higher yield and could best adapt to low-P availability under field conditions.

International audience; Northwestern Algeria is located where the Saharan Atlas borders the Saharan Platform along the South Atlas Front. The origin of the South Atlas Front is controversial, thus a detailed gravity and magnetic analysis constrained by seismic reflection profiles and well data were conducted to determine the structural configuration of this region. A residual gravity anomaly map created using upward continuation and a reduced to the pole magnetic anomaly map indicated a series of northwest-trending maxima anomalies parallel to the Atlassic orogeny folds and faults and east-trending maxima within the Benoud foreland basin. These maxima mostly coincide with Paleozoic basement uplifts based on seismic reflection profiles. Depth analyses based on upward continuation, and two-dimensional forward modeling of the gravity and magnetic data indicated that the source of the maxima are mainly 5 km in depth with the magnetic sources being approximately 0.5 km deeper than the gravity sources. The gravity and magnetic models indicate that the source bodies are steep-sided and coincide with interpreted faults from the seismic reflection profiles. The maxima anomalies are mainly caused by basement uplifts instead of variations in density and/or magnetic susceptibility in the Paleozoic or older basement lithologies. The South Atlas Front and the Saharan Atlas on the central and eastern portions of Algeria is governed by a thin-skinned tectonics style involving the Mesozoic-Cenozoic sedimentary cover. While the western part was probably controlled by a mixed thin- and thick-skinned tectonic style with the reactivation of deeply rooted Triassic and Jurassic faults during Tertiary compressive events in the interpreted Paleozoic basement. Our gravity and magnetic models illustrate a crustal architecture model of the Paleozoic basement which is consistent with a north-dipping basement normal fault between less deformed Saharan Platform than the more deformed Atlassic domain. Such a crustal model aids in determining the nature of the Atlassic orogeny as geological and geophysical studies have been determining the variations of structural styles along its entire length.

Organic matter water extract, or so-called ‘tea’, may be used to correct nutrient deficiencies in crops or enhance their defense systems. Such tea mixtures are prepared locally by Mediterranean farmers to offset a multitude of constraints, particularly a scarcity of organic manure or high synthetic input costs. However, the diverse range of tea production and usage practices and farmers' underlying rationales have yet to be thoroughly studied. Yet locally they constitute real alternatives that allow farmers to maintain their income levels while reducing reliance on chemical inputs. The main objective of this study was to gain insight into farmers' rationale and practices regarding the production of homemade dry manure tea (HMT) in North Africa, while also highlighting the benefits perceived by farmers. Nearly 50 interviews with farmers were thus conducted in three irrigated cropping areas in Morocco, Algeria and Tunisia. Our results showed that HMT is widely used in intensified family horticultural cropping systems that usually rely on drip irrigation and chemical fertilization. The analysis of farmers' practices revealed that HMT was generally made from aged manure that was pure or consisted of a mixture of sheep, cow or poultry dung. The production protocol varied in terms of drenching techniques, maceration time, container volume and type, and filtration techniques. Farmers applied the derived tea via the drip irrigation system, regularly or with a limited number of applications. The analysis of farmers' rationales and perceptions regarding HMT clearly highlighted that they felt that these practices played a positive role. HMT was considered to improve vegetative growth, yield and, to a lesser extent, soil properties. These benefits could in turn lead to decreased use of synthetic fertilizers by farmers, while boosting their income. The increased understanding of HMT and the underlying rationales showcased in this study could help scientists better analyze and assess these practices in the future. The findings could also facilitate improvement and wider dissemination of these practices to achieve more sustainable irrigation systems in the intensified irrigated cropping areas that abound in North Africa.

This research consists in analyzing the use of the digital communication strategy on social media. For this, we studied the case of the online travel and tourism agency Nreservi.com. The results showed that the agency adopts a digital communication strategy on social media and Facebook is the most used social media., La présente recherche consiste à analyser l'utilisation de la stratégie de communication digitale sur les réseaux sociaux. Pour cela nous avons étudié le cas de l'agence de tourisme et de voyage en ligne Nreservi.com. Les résultats ont démontrés que l'agence adopte une stratégie de communication digitale sur les réseaux et que Facebook est le réseau social le plus utilisé.

International audience

International audience; Modern intensive agricultural systems generally focus on the productivity of monocultures. They are characterized by a low diversity of crops, with uniform and symmetrical planting layouts. They largely rely on the utilization of chemical inputs. They are widely denounced for their negative environmental impacts. In this context, the ecological intensification framework proposes the exploitation of biodiversity in order to better achieve such ecosystem services and soil conservation. Intercropping, i.e., the simultaneous growth of two or more crops mixed in the same field, appears to have the potentialities to improve the productivity, resilience capacity, and ecological sustainability of agroecosystems through the intensification of such positive interactions between plants as facilitation and niche complementarity. Cereal-legume intercropping turns out to be effective in low-N agroecosystems, since legumes have the ability to fix atmospheric nitrogen via their symbiosis with rhizobia. This fixed N, in turn, benefits the cereal through various ecological processes. The objective of the project is to improve the benefit of legumes for intercropped cereals in low-input agroecosystems through the management of plant-plant and plant-microbe interactions. The nitrogen-fixing symbiosis requires phosphorus and iron to be efficient. While these nutrients are prone to be lacking in N-limited agroecosystems, as is the case in Mediterranean agroecosystems, plant-plant interactions and rhizobacteria and mycorrhiza interactions seem to play an important role in their acquisition and efficient utilization. We propose the development of a participatory research project in four Mediterranean agroecosystems. Agronomic and environmental diagnosis will be performed in the field to assess N and P biogeochemical cycles, as well as Fe availability, in combination with the plant performances and the diversity of soil microorganisms. Molecular identification of soil microorganisms from the most productive sites will be done and research of genes for tolerance to Fe- and P-deficiencies will be realized. Glasshouse experiments involving various cultivars of cereals and legumes, as well as the previously identified microorganisms, will be done in order to disentangle the various mechanisms of nutrient acquisition, sharing, and transfer between plants. Other experiments will assess the effects of cereal-legume-microbe interactions on the development and architecture of the plant root systems and root hair development. The lines of research are integrated with a strategy of functional ecology on plant-microbe-soil interactions in the agroecosystems of Gabes (Tunisia), Boumedfaa (Algeria), Beni Mellal (Morocco), and Thessaloniki (Greece). Using multidisciplinary and innovative approaches, the program will provide novel knowledge and understanding of agroecosystem management for food production.

International audience; Phosphorus (P) deficiency is a critical environmental constraint that affects the growth and development of several legume crops that are usually cultivated in semi-arid regions and marginal areas. P-deficiency is known to be a significant limitation for symbiotic nitrogen fixation (SNF), and variability in SNF is strongly interlinked with the concentrations of inorganic phosphate (Pi) in the nodules. To cope with P-deficiency, legumes trigger various adaptive responses, including the induction and secretion of acid phosphatases (APases) and phytases, maintenance of Pi homeostasis in nodules and other organs, and improvement of oxygen consumption per unit of nodule mass. While the induction of phytases is a universal response to P-deficiency in higher plants, the physiological role of these enzymes in nodules of N2-fixing legume is crucial but still not fully understood. Understanding the role of APases and phytases activities in response to environmental constraints may be important in developing strategies to improve the tolerance of the nodulated legume to low-P availability. In this review, we summarize and discuss recent advances in the understanding of the expression of phytases within the nodules of legumes under P-deficiency and address whether this expression might influence the nodule respiration and contribute to adaptation of N2 fixing legumes to low-P environments. Finally, we will provide perspectives on future directions for research in this field.

International audience; Few studies have focused on the trophic functioning of the reservoirs in Algeria. The study of the gut contents of fish species, as well as the analysis of the stable isotopes of 13C and 15N in the environment, were carried out on samples collected during spring 2010 in two reservoirs: Ghrib and Harreza of the upper Cheliff plain (Algeria) within a semi-arid climate zone. In each of the reservoirs, 13C and 15N were measured in sediments, particulate organic matter (POM), macrophytes, zooplankton, zoobenthos and fish. The isotopic analysis shows that the carbon values that supply both reservoirs, Ghrib and Harreza, were −31.16 ± 0.05 < 13C < −18.01 ± 0.21‰ and −30.82 ± 0.07 < 13C < −17.24 ± 3.50‰, respectively. The carnivorous fish Sander lucioperca, and Abramis brama, an omnivorous fish, were allocated to the top of the food web in Ghrib and Harreza reservoirs, respectively. In the latter, a reservoir with low hydrodynamism and depth, the food web is simpler with a single fish species, which benefits from both benthic and pelagic sources. In Ghrib, a deeper dam with stronger hydrodynamics, only the riverine crab Potamon algeriense exploits the benthic sources, whereas fish mainly feed on zooplankton.

Effective quantitative and qualitative management of water for irrigation is crucial in many regions and the use of reclaimed water is a possible solution. Quantifying the impact of the use of such water is thus important. Using life cycle assessment methodology, this study analyzes the impact of water reuse irrigation and farmers’ practices in greenhouse cucumber production. Three scenarios concerned sources of water for irrigation and agricultural practices: the first scenario used surface water including reclaimed water, the second used groundwater. The third scenario resembled the first but also accounted for fertilizer application based on theoretical cucumber requirements. The third scenario showed 35% less fertilizer is required than the quantities farmers actually use. Our results show that the higher environmental impact of irrigation using reclaimed water than using groundwater is mainly due to over-fertilization. Comparison of the first and third scenarios also showed that the reduction in the environmental impact under the third scenario was significant. We conclude that LCA is a useful tool to compare the impacts of different water sources and farmers’ irrigation/fertilization management practices, and in particular, that the quantity of nutrients in reclaimed water should be deducted from the actual amount applied by the farmers. HIGHLIGHTS Evaluate the environmental impact of indirect case of reclaimed water reuse versus groundwater for agricultural irrigation using life cycle assessment (LCA).; Our field study was conducted in the Mediterranean region of Tipaza, Algeria focusing on data from farmers' work schedule.; We compared the performance of irrigation using reclaimed water and groundwater to identify which sub-system had the most impact.; Discuss farmers' fertilization practices in the area compared with theoretical recommendations.; Our study could be used as basic data to farmers to respect the doses of fertilizer application with different sources of water irrigation.

International audience; PEM Fuel Cells (PEMFCs), fueled by hydrogen, are electrochemical devices that convert hydrogen to useful power and two by-products: heat and water. They cover an important part of power applications namely in the transportation area, and in other practical applications that are either stationary or portable. In particular, the domestic refrigerator is one of the daily and indispensable applications but with a high-energy demand due to the high running time cycles. This work is a technical assessment of the feasibility of building a coupled "PEM Fuel Cell - Refrigerator" system. Real technical data for the refrigerator are collected, processed and evaluated. The obtained results show reasonable flows consumption rates. In fact, the refrigerator requires a flow rate of 1.607 slpm of hydrogen and 8 slpm of air at a pressure of respectively 3 atm and 1 atm. The water is produced at a rate of 1.285 10(-3) slpm. The annual amount of hydrogen consumed by the refrigerator is estimated to 28, 47 kg. The energy provided to the refrigerator is about 130 W and the energy needed by the air compressor is 28, 24 W. A technical solution is suggested at the end of this work to reduce the start and stop cycles of the fuel cell.

International audience; Low phosphorus (P) availability is a primary factor that limits the production of common bean (Phaseolus vulgaris L.) in many parts of the world, especially when plant growth depends on N2 fixation. In order to understand how common bean copes with this nutritional constraint, two recombinant inbred lines (RILs) of common bean namely RILs 115 and 147 were studied in the field conditions during three growing seasons from 2012 to 2014. At flowering stage, plants were harvested and analyzed for their nodulation, growth, P content and yield. Results showed that for RIL115, the nodulation (43%), shoot (28%) and root growth (32%) was higher than for RIL147 in a low-P availability soil whatever the growing season. In addition, RIL115 had better growth and efficiency in use of P for the rhizobial symbiosis (7.29 mg nodule dry weight mg−1 nodule P) about twice higher may be involved in tolerance to low-P, and to be a useful marker for field data. At harvest, the RIL115 showed higher grain yield (1146 kg ha−1) than the RIL147 (1045 kg ha−1). It is concluded that the genotype of RIL 115 had a higher yield and could best adapt to low-P availability under field condition.

International audience; This paper deals with an adaptable semi-analytical model to calculate the open-circuit and armature reaction field distributions as well as the electromagnetic performances in many structures of permanent-magnet synchronous machines (PMSMs). It is based on the multi-layer models considering the iron permeability with the convolution theorem (i.e., Cauchy's product theorem) using the harmonic modeling technique (or the Maxwell-Fourier method). The 2-D semi-analytical model can be used for surface-mounted-inset-mounted or spoke-type PMSMs with different permanent-magnet (PM) magnetization patterns, winding structures, internal/external rotors, and slotless or slotted stators without the need to adopt the model equations to a specific PM machine type. For example, this scientific contribution has been applied to three types of PMSM with different topologies, viz.: i) slotted surface-mounted external rotor PMSM; ii) slotted surface-inset internal rotor PMSM; and iii) slotless external rotor spoke-type tangential PMSM. Finally, the results of semi-analytical method are compared with those found by the finite-element method.

International audience; In Algeria, drought affects grain weight and modified its biochemical composition. The present study was conducted to evaluate the effect of two water supplies (100% FC, 30% FC) on grain weight and composition of five genotypes of durum wheat (Triticum durum Desf.). We also examined the effects of shading of peduncle, spike and the entire plant and excision of awns, flag leaves and foliar system on grain weight, starch and amylose/amylopectin ratio. From this study, we found that grain weight was significantly reduced by the application of water deficit. However, this action is greatly related to genotype type. It is admitted that this trait is strongly conditioned by the grain filling process. The morphological characteristics of plants were implicated to grain weight elaboration. Among organs studied, the photosynthetic rate of spick and reserves remobilization from stem announced determinant in grain filling. We found also that starch content which is associated to amylose/amylopectin ratio is strongly related to grain weigh. Finally, grains weight variations were associated to starch content and mainly related to the water supply condition.

Actes du colloque International L’éducation et la prévention routière « Conducteurs et piétons : quelle prévention pour réduire les accidents de la circulation ? »; International audience; L’objectif essentiel de cet article est de clarifier l’effet du véhicule dans les normes de la sécurité routière pour une stratégie de lutte contre les accidents de la circulation en Algérie. Cette vision constitue une approche multiple pour analyser et comprendre l’insécurité routière chez les usagers de la route. Mettre la lumière sur les statistiques et les observations liées à ce sujet permettra de déterminer les caractéristiques de la stratégie routière mise en place en Algérie et voir son efficacité.

International audience; The crustal structure beneath the northeastern continental part of Algeria is still largely unknown. Here we use potential field data processing, modeling and interpretation in order to investigate the deep sedimentary layers of this area and the transition with the basement. Indeed the gravimetric and magnetic field maps unveil the main geological domains of North Algeria: the AlCaPeKa domain, the Tellian Nappes, the Atlas and the South-Atlasic Fault (SAF). Our modeling approach combines the prediction of gravimetric and magnetic field signals along 4 N–S profiles that cross those domains and using constraints from seismic lines. The resulting cross-sections reveal the roots of the main E-W tectonic detachments of this area: the northern Suture Zone, the Tell Front, and the SAF. It seems that they are all initiated in the lower crust, nearby the continental/oceanic crustal transition for the Suture Zone, and several tenths of kilometers south from this transition for the Tell Front and the SAF detachments. Using these detachments, the lower parts of the crust are sometimes uplifted to only 5 km deep in the crust, while the upper crust is sometimes thickened to reach 15 km of thickness. Large magnetization and density contrasts are observed right beneath the Suture Zone.

International audience

Poster; International audience; The characterization method of High Temperature Superconducting (HTS) bulks developed by GREEN lab described in previous papers is based on the measurement of the complete penetration magnetic field BP. This characterization method allows determining the critical current density JC and the n-value of the power law. The Jc inhomogeneity in axial and radial directions has to be taking account in the process of characterization. Especially the position of the hall sensors related to the seed of HTS bulk is very important and is studied and described in this paper. Many experiments were made to demonstrate this and numerical simulations were developed at the same time to validate theoretical deductions. This work should be a real improvement for the characterization of superconducting bulks.

Poster; International audience; In the design phase of the inductor required for the magnetization of High Temperature Superconductor (HTS) bulks, modeling and simulation are necessary for the design of this inductor. In this paper we have developed an analytical model to calculate the inductance for a coil of a ferromagnetic circuit with gap including a superconducting pellet. This model is based on the determination of the magnetic vector potential from solving the Laplace’s and Poisson’s equations in different regions of interest, using the separation of variables method in which the Cartesian coordinates are used. The boundary and continuity conditions between regions are considered to determine the global solution. This analytical resolution is carried out using a computation code developed under MATLAB. The results obtained are compared with those obtained by a numerical simulation based on the finite element method implemented under COMSOL. A remarkable concordance is observed between both approaches.

International audience; While increased P-hydrolysing acid phosphatases (APase) activity in bean nodules is well documented under phosphorus (P) limitation, gene expression and subcellular localization patterns within the N2-fixing nodule tissues are poorly understood. The aim of this research was to track the enzyme activity along with the intra-nodular localization of fructose-1,6-bisphosphatase (FBPase), and its contribution to P use efficiency (PUE) under symbiotic nitrogen fixation (SNF) in Phaseolus vulgaris. The FBPase transcript were localized in situ using RT-PCR and the protein activity was measured in nodules of two contrasting recombinant inbred lines (RILs) of P. vulgaris, namely RILs 115 (P-efficient) and 147 (P-inefficient), that were grown under sufficient versus deficient P supply. Under P-deficiency, higher FBPase transcript fluorescence was found in the inner cortex as compared to the infected zone of RIL115. In addition, both the specific FBPase and total APase enzyme activities significantly increased in both RILs, but to a more significant extent in RIL115 as compared to RIL147. Furthermore, the increased FBPase activity in nodules of RIL115 positively correlated with higher use efficiency of both the rhizobial symbiosis (23%) and P for SNF (14% calculated as the ratio of N2 fixed per nodule total P content). It is concluded that the abundant tissue-specific localized FBPase transcript along with induced enzymatic activity provides evidence of a specific tolerance mechanism where N2-fixing nodules overexpress under P-deficiency conditions. Such a mechanism would maximise the intra-nodular inorganic P fraction necessary to compensate for large amount of P needed during the SNF process.

International audience

International audience; In this paper, a method to calculate the winding factor by only considering stator parameters without the rotor ones is developed. This is interesting because it allows the separation of the stator and rotor design, unlike the existing methods in the literature. A general method based on the matrix representation of a winding is presented. This approach requires the knowledge of four parameters : i) slots number, ii) phases number, iii) layers number, and iv) single-phase spatial distribution. A new feature of the multi-layer windings is introduced, it is called false-zero windings, which is divided into two categories: i) α-windings (i.e., odd false-zero windings), and ii) β-windings (i.e., even false-zero windings). The windings having no false-zero are categorized as γ-windings. The calculations are applied for single and multi-phase/-layer windings. The results of the comparison are satisfactory. The code used for the calculation is given in Appendix.

International audience; In this paper, an analytical approach allowing the prediction of iron-core losses in flux-modulated permanent-magnet synchronous machines. According to the Maxwell-Fourier method (viz., the multi-layer model) and Cauchy's product theorem, the magnetic field distribution is determined in different parts of machine by considering the iron permeability on the basis of the solving both Poisson's and Laplace's equations. Next to the dc bias flux density and the minor hysteresis loops, which are taken into account, the Bertotti's model and the flux variation locus are employed to calculate the iron-core losses under load and no-load conditions in post-processing from the magnetic field analytical calculation. Finally, in order to validate the proposed analytical method, the results are verified by the comparison with the finite-element method. The comparisons show good results of the proposed model.

International audience; Road safety is a major issue both in the number of victims on the roads and in the economic cost of these accidents on the Algerian economy. The fight against road safety is a priority state concern and this fight must be waged against the most vulnerable road users, as travel continues to increase in Algeria. The objective of the diagnosis of the road traffic accident report for the years 2005, 2010 and 2017 is to identify and quantify the malfunctions that characterize road accidents. These malfunctions will be described by means of indicators such as accident or damage ratios, levels of road use, and others. The fight against insecurity on the roads is a challenge that requires a profound change in attitudes and a relentless mobilization of state services to protect the lives of current and future citizens.; La sécurité routière constitue un enjeu majeur tant par le nombre des victimes sur les routes que par le poids du coût économique de ces accidents sur l’économie algérienne. La lutte contre l’insécurité routière est une préoccupation prioritaire d’État et cette lutte doit être menée envers les usagers de la route les plus vulnérables, vu que les déplacements ne cessent de croitre en Algérie. L’objectif du diagnostic du bilan des accidents de la circulation routière des années 2005, 2010 et 2017 est d'identifier et de quantifier les dysfonctionnements caractérisant les accidents de la route. Ces dysfonctionnements seront décrits par le moyen d'indicateurs tels que les ratios d'accidents ou d'avarie, les niveaux d'utilisation de la route, et autres. La lutte contre l’insécurité sur les routes est un défi qui impose une évolution en profondeur des mentalités et une mobilisation sans relâche des services de l’État dans le but de protéger la vie des citoyens actuels et futurs.

International audience; This paper presents a two-dimensional (2-D) exact subdomain technique in polar coordinates considering the iron relative permeability in 6/4 conventional switched reluctance machine (SRM) supplied by sinusoidal waveform of current. The general solutions of magnetic vector potential are obtained by applying the interfaces conditions (ICs) in both directions (i.e., r- and -edge ICs). The magnetic field is used to predict the iron core losses by using an analytical approach based on the Bertotti’s model and the flux variation locus (FVL). Finally, the electromagnetic performances results have been performed and compared with the 2-D finite-element (FE) method (FEM). The comparisons with FEM show good results of the proposed approach.

International audience; This paper presents a magnetic field analysis of surface-mounted permanent magnet (PM) motor using Schwarz-Christoffel (SC) mapping method, taking account any eccentric PM shape and for varied magnetization pattern. Two rotor shapes with radial and parallel magnetization are proposed: The first has a conventional PM shape, while the other has an eccentric PM shape. For that, the calculated magnetic field in the middle of the air-gap using conformal mapping (CM) method and its harmonic content are compared for the four motors. Further, the influence of rotor shape and PM's magnetization on the back EMF and its harmonic content and on the cogging torque and electromagnetic torque is also discussed. Finally, finite-element method (FEM) is used to verify the obtained results, showing good agreement between both methods.

Oral; International audience; Toutes les méthodes d’aimantation des supraconducteurs sont basées sur la variation du champ magnétique appliqué qui résulte des caractéristiques de l’inducteur utilisé. Dans ce papier nous avons développé un modèle analytique pour montrer l’effet de la présence d’une pastille supraconductrice sur la valeur de l’inductance d’une bobine circulaire de section transversale rectangulaire placée dans un circuit ferromagnétique avec entrefer. Ce modèle est basé sur la détermination du potentiel vecteur magnétique à partir de la résolution les équations de Laplace et de poisson dans les différentes régions d’intérêt en utilisant la méthode de séparation des variables. Cette résolution analytique s’effectue à l’aide d’un code de calcul développé sous MATLAB. Les résultats obtenus sont comparés avec ceux obtenus par une simulation numérique basée sur la méthode des éléments finis implémentée sous COMSOL. Une concordance remarquable est observée entre les deux résultats.

Oral; National audience; L’utilisation des matériaux supraconducteurs comme écrans magnétiques ou aimants permanents dans les applications en génie électrique tels que les moteurs électriques est envisagée depuis quelques années. Dans cet article est présenté un bilan des avancées des travaux sur les écrans et aimants supraconducteurs à travers l’étude des propriétés des différents matériaux, leurs performances et leurs applications. Les deux paramètres importants de ces éléments sont le champ magnétique de pénétration complète BP et la densité de courant critique JC. Ces paramètres sont liés aux performances d’écrantage et d’aimantation des matériaux considérés.

Poster; National audience; L’aimantation des supraconducteurs, notamment par des champs magnétiques impulsionnels, nécessite le dimensionnement correct de l’inducteur. Dans cet article, nous avons développé un modèle analytique dans le but de calculer l’inductance d’une bobine dans un circuit ferromagnétique avec entrefer contenant une pastille supraconductrice. Dans ce modèle, il s’agit de résoudre les équations de Laplace et de Poisson dans différentes régions d’intérêt à travers le potentiel vecteur magnétique. La résolution analytique s’effectue à l’aide d’un code de calcul développé sous MATLAB. Une simulation numérique sous COMSOL est également effectuée pour ce problème. Les deux méthodes sont comparées et les résultats coïncident parfaitement. L’expression analytique de l’inductance obtenue peut ainsi servir à dimensionner l’inducteur du système d’aimantation pour les supraconducteurs.

National audience; Toutes les méthodes d’aimantation des matériaux supraconducteurs sont basées sur la variation du champ magnétique appliqué qui résulte des caractéristiques de l’inducteur utilisé. Cependant, le moyen le plus commode et le plus courant est d'utiliser un champ magnétique pulsé. Dans ce travail, nous avons pu développer un modèle analytique qui a pour but de montrer l’effet de la présence d’une pastille supraconductrice sur la valeur de l’inductance d’une bobine circulaire de section transversale rectangulaire placée dans un circuit ferromagnétique avec entrefer. Ce modèle est basé sur la détermination du potentiel vecteur magnétique à partir de la résolution des équations de Laplace et de Poisson dans les différentes régions d’intérêt en utilisant la méthode de séparation des variables. Les coordonnées cartésiennes sont employées dans cette étude. Cette résolution analytique s’effectue à l’aide d’un code de calcul développé sous MATLAB. Les résultats sont ensuite comparés avec ceux obtenus par une simulation numérique basée sur la méthode des éléments finis implémentée sous COMSOL. Une concordance remarquable est observée entre les deux résultats.

The authors would like to thank Thierry Lubin and Alexandre Colle for their useful discussions on this topic.; International audience; The development of bulk magnets based on REBCO type superconductors that can generate up to 17 T requires the implementation of a magnetization system, sometimes pulsed. Therefore, at least one coil around the High Temperature Superconducting (HTS) bulk is required. In this paper, we suggest an analytical approach in order to assess the magnetic vector potential and to compute the inductance of a coil having a rectangular cross-section and concentric with a magnetic circuit including an air-gap. On a proposed geometry, analytical results are compared with those obtained by using Finite Element Analysis (FEA). The gained analytical expressions give accurate results with an error less than 1% on the inductance value of the coil. The induced current density and trapped magnetic field in a HTS bulk during a Pulsed Field Magnetization (PFM) are also calculated using the proposed analytical expressions of the magnetic vector potential combined with an integral method. The achieved results show a remarkable match with those obtained with COMSOL.

International audience; Phosphorus (P) deficiency initiates a myriad of transcriptional, biochemical and physiological responses stimulating either the root’s extracellular abilities to acquire soil P in the rhizosphere or optimize its intracellular use efficiency and allocation through all plant organs. Enhancing activity of acid phosphatase (APase) to acquire and remobilize Pi from organic P compounds is one important strategy for improving plant P nutrition. The release of APase to the rhizosphere is a typical and almost universal P-starvation response in higher plants. However, relatively little is known about the functions of intracellular APase in legume nodules. The aim of this review was to track the enzyme activity along with the intra-nodular localization of APase, and its contribution in the rhizobial symbiosis tolerance to P-deficiency. Our findings have revealed that expression of APase and phytases genes and activities of the corresponding enzymes were positively correlated with increases both of the P use efficiency for N2 fixation and nodule O2 permeability in the rhizobial symbiosis with legumes. The induced enzyme activity and the marked transcripts localization of APase and phytase in nodule cortex would control nodule respiration and contribute to adaptation of nodulated legumes to low-P availability. Thus, the increase of APase and phytase activities in legume nodules supports a physiological role of these enzymes in the regulation of nitrogenase activity in connection with the nodule-P status, and opens up a new scenario for a better understanding of the regulation of N2 fixation in legumes.

13 Pags.- 3 Figs., The soils of the Mediterranean Basin are the products of soil processes that have been governed by a unique convergence of highly differentiated natural and anthropogenic drivers. These soils are expected to be dramatically affected by future climate and societal changes. These changes imply that suitable adaptive management strategies for these resources cannot simply be transposed from experiments that are performed in other regions of the world. Following a framework that considers the chain of “drivers-soil process-soil capital-ecosystem services/disservices,” the paper review the research undertaken in the Mediterranean area on three types of Mediterranean soil degradation than can be expected under global change: (i) soil losses due to the increase of drought and torrential rainfall; (ii) soil salinization due the increase of droughts, irrigation, and sea level; and (iii) soil carbon stock depletion with the increase of temperature and droughts. The possible strategies for mitigating each of these degradations have been largely addressed and are still studied in current research projects. They should include changes in agricultural practices, soil water management, and vegetal material. As a pre-requisite for the site-specific adaptations of such mitigation strategies within viable Mediterranean agrosystems, it is highlighted that methodological advances are necessary in integrated assessment of agricultural systems and in finer resolution soil mapping.

The objective of this study is to analyze the hydro-climatic regimes of the watershed of Mitidja West, and then try to evaluate the influence of climate on superficial flows. Rainfall data and databank for monthly discharges come from the National Agency of Hydraulic Resources (ANRH), rainfall are recorded from 23 rainfall stations distributed over the watershed and whose size varies from one station to another, and Time series of discharges data are generally from 1987 to 2012, but vary in duration. However, we noted that flows have been subjected to ruptures of 1975 until the middle of the 1980s. However, this reduction is due to a the climate impact associated with precipitation which decrease significantly since the end of the 75 years; or an anthropogenic impact due to the many hydraulic infrastructure development since 1985. Thus, for the simulation of the discharges from the rains, the efficiency of the model to simulate monthly discharges of the basin is given by the analysis of the criterion of Nash, of which it gave satisfactory values ​​superior to (60%), we can say, afterwards, that the GR2M model has a certain efficiency to simulate the discharges in the monthly time step and to guarantee a better understanding of the hydrological behavior of the basin.

International audience; In order to design multi-phases permanent-magnet (PM) synchronous machines (PMSMs), a simpli…ed analytical method is used to calculate the various geometrical parameters. The winding of the machines is concentric with two layers and the PMs are mounted on the rotor surface. The sizing model is coupled to an optimization process based on genetic algorithm (AG). The Pareto front obtained from the optimization, made it possible to choose the optimal solution. The optimal variables are injected into the model to calculate the di¤erent parameters. The optimization results are then used for two-dimensional (2-D) …nite-element simulation, where a power balance is established for each multi-phases PMSMs.

International audience; This study consists in presenting an experimental study of an axial superconducting rotating machine. The inductor of the machine is based on the principle of magnetic concentration using bulks superconductors. The parameters of the machine are identified experimentally by carrying out static, dynamic, at the ambient temperature and at 77 K.

Poster; International audience; The development of cryo-magnets made with REBaCuO superconductors allows us to consider the generation of very intense magnetic field (up to 17 Tesla). This can be done with a pulsed magnetization system including one coil in the simplest case. Usually, sophisticated and complicated numerical modeling is needed to calculate electromagnetic characteristics of the inductor. Such modeling can be done, for example, using a Finite Element Analysis software to achieve a complex problem with the risk to need a readjustment of used parameters each time that we feel the numerical results are not satisfactory. For more flexibility, and in particular in the design stage, an analytical approach is proposed in the present paper with some assumptions, to calculate the magnetic vector potential components and deduce the magnetic field and inductance of the coil. This is done by the resolution of Laplace’s and Poisson’s equations in each region of interest, under Dirichlet and Newman conditions. The set of solutions is obtained with Fourier analysis and the magnetic field's expressions are given by special functions like Bessel and Legendre ones. Obtained results for the same proposed system is modeled and simulated with COMSOL Multiphysics, by the use of finite elements. Both approaches are compared and discussed.

Poster; International audience; Our basic method to characterize HTS pellets, which has been presented in earlier publications, is based on the measurement of their complete penetration magnetic flux density BP. The method allows assessing the critical current density JC and the n-value through the classical power law model modeling the magnetic behavior of pellets and the direct measurement of BP. A first method used two slightly axially separated HTS disks to determine BP in the gap between the disks. However, this first method exhibits two main disadvantages. The first disadvantage is that the magnitude of the derived values depends on the spacing e between the two pellets. The second one is that the two pellets ought to be strictly identical for the method to lead to representative values of a given pellet. To overcome those constrains and limitations, we have been looking for a new improved method that relies only on the measurement involving a single pellet. The following work introduces the principle of this new method. The main idea is thus to deduce BP from the magnetic flux density measured at the center of the top surface of the pellet referred to as BT when the applied magnetic flux density Ba equals BP. The influence of the applied magnetic flux density ramping rate and the geometric dimensions of the pellet on the ratio BP /BT is studied and used to assess BP from the measured BT. It is shown that the proposed method allows achieving a substantial improvement on the accuracy of the Jc and n-value measurements of a given superconducting disk over the past method based on two HTS pellets.

International audience; This paper presents a general analytical subdomain model for the computation of magnetic field distribution in any number of stator slots and rotor poles with and without electrically-excited, permanent magnet-excited and hybrid-excited multiphase flux switching machines (FSM) topologies. The goal of this work is to elaborate an analytical general method based on subdomain model for predicting magnetic field in any FSM topology with defining in advance the number of subdomains and affect the general form of vector potential in each subdomain. The presented general subdomain method is comparable to finite element method (FEM) where the mesh elements can be compared to the number of harmonic terms used in each subdomain.

International audience; This paper deals with the nonlinear analytical harmonic modeling (HM) of three phases, and 6/4 conventional switched reluctance machine (SRM). The proposed model consists in computing magnetic field distribution and electromagnetic performances of an SRM with conventional winding. Because an SRM has inherently nonlinear characteristics, the analytical subdomain model that does not take into account the saturation has a limited accuracy. This is due to the assumption of infinite tooth permeability. The new analytical model (AM) based on the HM technique, which overcomes this limitation, is presented with the consideration of the local magnetic saturation on the stator and rotor teeth. The results obtained with the nonlinear AM have been compared with the linear AM based on the subdomain method (i.e., without the saturation effect) and nonlinear finite-element method solutions.

Oral; International audience; The use of superconductor in electrical engineering allows to improve performance in terms of power density for example. However, their operation requires cooling them at very low temperatures. Therefore it needs a cryogenic environment. The main cryogenic used are liquid helium and liquid nitrogen. Increasingly the cryocoolers are used in applications of superconductors. In this article two applications of crycooler used in electrical engineering are presented, a synchronous motor superconducting inductor and the electrical superconducting wire characterization bench.; L’utilisation des supraconducteurs en génie électrique permet d’obtenir des performances améliorées en termes de puissance massique par exemple. Cependant leur fonctionnement nécessite de les refroidir à des températures très basses. Il y a donc nécessité d’un environnement cryogénique. Les principaux cryogènes utilisés sont l’hélium liquide et l’azote liquide. De plus en plus les cryocoolers sont utilisés dans les applications des supraconducteurs, Dans cet article deux applications en génie électrique de ces crycoolers sont présentés, un moteur synchrone à inducteur supraconducteur et un banc de caractérisation électrique de fil supraconducteur.

Low availability of phosphorus (P) is a major constraint to legume production, and efforts are being made to identify legume genotypes with tolerance to low P and greater P use efficiency (PUE). Cowpea (Vigna unguiculata L.) genotypes vary in their adaptation to low-P soils. In order to investigate to what extent this variation may be related to PUE for symbiotic nitrogen fixation (SNF), five genotypes, Adrar, El Kala, Djenet, Tizi Ouzou and Bejaia, were grown in semihydroponic culture with sufficient versus deficient P supply. At the flowering stage, the biomass of plants and nodules and their P contents was determined after measuring the quantity of N2 fixed. The results showed that nodule and shoot biomass were less when P was deficient. The genotypes that presented the maximum growth during the experiment presented a high efficiency in use of the rhizobial symbiosis calculated as the slope of plant biomass regression as a function of nodulation. Under P-deficiency, efficiency in use of P for SNF was significantly increased in the genotypes El Kala, Djenet and Adrar and accompanied with an increase of the efficiency in use of the rhizobial symbiosis. Hence the large differences show that traits for more P uptake-efficient plants exist in the tested cowpea genotypes. This opens the possibility to breed for more P uptakeefficient varieties as a way to bring more sparingly soluble soil P into cycling in crop production and obtain capitalisation of soil P reserves.

National audience; Under phosphorus (P) deficiency, sensitivity of the N2-fixing legumes increases since the large amount of P-dependent carbon and energy turnover required during N2fixation are not satisfied. However, despites the fact that these crops have been widely characterized under P-deficiency and a number of tolerance traits have been identified, abilities of the nodules to cope with this environmental constraint have still to be further investigated. Increases both of activity and gene expression of acid phosphatases (APases) are among mechanisms that lead to increase both of N2fixation and nodule respiration under P-deficiency. Our findings have revealed that activities and differential expression of phytase transcripts were positively correlated with increases both of the rhizobial symbiosis efficiency (EURS) and nodule O2 permeability. Under P-deficiency, this positive correlation was more significant for the P-efficient RIL115 than for the P-inefficient RIL147. It is concluded that the induced enzyme activity and the marked transcript localization of this phytase in nodule cortex would control nodule respiration and contribute to adaption of nodulated legumes to low P availability.

International audience; Low phophorus availability in about 40% of the world’s arable land limits crop yield, most particularly for leguminous crops when their growth depends upon symbiotic N2-fixation (SNF). Therefore, our work aims to increase the phosphorus use efficiency (PUE) for SNF, and its contribution to a more effective coupling between the P and N bio-geochemical cycles. Myo-inositol hexakisphosphate (phytate) constitutes the main source of organic P in soils, but is unavailable to plants. Phytases are the only phosphatases able to hydrolyse phytate efficiently into inorganic Pi, thus increasing P bio-availability for plants. In this work we show by in situ RT-PCR, the expression of a purple acid phytase within the inner-cortex of Phaseolus vulgaris root-nodule (Lazali et al., 2014). Also histidine acid- and - propeller- phytases (HAP and BPP) were found among legumenodulating rhizobia with major expression in nodule infected-cells. Moreover, phosphoenol pyruvate phosphatase (Bargaz et al. 2012) and trehalose 6P phosphatase (Bargaz et al. 2013) were discovered in nodules with puzzling localization. The nodular expression of all these genes and the enzymatic activity of their products increased significantly under P-deficiency. They varied among recombinant inbred lines of P. vulgaris that were shown to contrast in their PUE for SNF. It is concluded that the differential expression of bacterial and plant phosphatase-genes in nodules offers a new understanding of the N2-fixing legume physiology and its specific P requirements. The potential of these phosphatase-genes as molecular markers for adaptation of legume crops in low-P soils and their contribution to a virtuous cycle of P and N fertility will be addressed in relation with the interdisciplinary research strategy of the FABATROPIMED federative project of Agropolis Montpellier.

International audience; Les auteurs comparent les performances électromagnétiques de deux machines polyphasées à aimants pour l'application Mild Hybrid. Cette comparaison a été effectuée à l'aide de simulations numériques en deux dimensions (2D). La meilleure machine a été déterminée à l'aide d'une étude énergétique (i.e., pertes, couples, rendement) selon un cahier des charges. Dans cette étude, le bobinage concentrique à double couches a été utilisé et la synthèse du bobinage est basée sur la méthode "des étoiles des encoches" et sur la décomposition en série de Fourier de la force magnétomotrice (FMM).

Diminuer les engrais minéraux et produit phytosanitaires issus de la pétrochimie, devient essentiel pour la sécurité alimentaire et l'impact environnemental de la production agricole. Ceci implique de nouvelles orientations pour la sélection des légumineuses, en particulier dans les systèmes culturaux de production de grains. La faible disponibilité du phophore dans près de 40% des terres cultivables de la planète limite le rendement des légumineuses, d'autant plus quand leur croissance dépend de la fixation symbiotique de N2 (FSN). En conséquence notre objectif est d'accroître l'efficacité d'utilisation du phosphore (EUP) pour la FSN, et sa contribution au couplage des cycles biogéochimiques de N et P par un cercle vertueux de fertilité qui serait associé à l'usage de symbioses à forte EUP pour la FSN. Cette hypothèse est étudiée dans le cadre de la stratégie de recherche interdisciplinaire du grand projet fédérateur FABATROPIMED d'Agropolis-Montpellier, dont l'objectif global est d'accroître les bénéfices écosystémiques des légumineuses pour les systèmes céréaliers, par une ingénièrie des interactions entre les micro-organismes des sols et les légumineuses pour acquérir et utiliser plus efficacement l'azote et le phosphore. Les activités in campo de cette stratégie seront présentées selon une approche participative avec des génotypes de légumineuses contrastant en EUP pour la FSN dans des agroécosystèmes représentant diverses situations agroclimatiques et socioécologiques en zones méditerranéennes ou tropicales

International audience; This paper presents an analytical method based on subdomain method for the computation of open circuit, armature reaction and on-load magnetic field distribution in integer slot winding parallel double excitation and Spoke-Type tangential permanent-magnet machines. The proposed model takes into account for stator and rotor slots tooth tips and shape of polar piece. A 2D exact analytical solution of magnetic field distribution is established. It involves solution of Laplace's and Poisson's equations in semi-closed stator and rotor slots, airgap, buried permanent magnets into rotor semi-closed slots, and non magnetic region under magnets. Obtained exact analytical results of open circuit, armature reaction and on-load magnetic field distribution are verified with those issued from finite element method (FEM)