81 research outputs found

    MHAV: multitier heterogeneous adaptive vehicular network with LTE and DSRC

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    Enabling cooperation between vehicles form vehicular networks, which provide safety, traffic efficiency and infotainment. The most vital of these applications require reliability and low latency. Considering these requirements, this paper presents a multitier heterogeneous adaptive vehicular (MHAV) network. Comprising of transport operator or authority owned vehicles in high tier and all the other privately owned vehicles in low tier, integrating cellular network with dedicated short range communications. The proposed framework is implemented and evaluated in Glasgow city center model. Simulation results demonstrate that the proposed architecture outperforms previous multitier architectures in terms of latency while offloading traffic from cellular networks

    The Dirac field in Taub-NUT background

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    We investigate the SO(4,1) gauge-invariant theory of the Dirac fermions in the external field of the Kaluza-Klein monopole, pointing out that the quantum modes can be recovered from a Klein-Gordon equation analogous to the Schr\" odinger equation in the Taub-NUT background. Moreover, we show that there is a large collection of observables that can be directly derived from those of the scalar theory. These offer many possibilities of choosing complete sets of commuting operators which determine the quantum modes. In addition there are some spin- like and Dirac-type operators involving the covariantly constant Killing-Yano tensors of the hyper-K\" ahler Taub-NUT space. The energy eigenspinors of the central modes in spherical coordinates are completely evaluated in explicit, closed form.Comment: 20 pages, latex, no figure

    Qualité des eaux de surface et souterraine de la région de Taza (Maroc) : bilan et situation des eaux

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    L’objectif de ce travail est de cerner l’état de la pollution des eaux superficielles et souterraines de la région de Taza (Maroc). Pour ce faire, une étude hydrochimique a été réalisée. Cette dernière est basée surla détermination des paramètres physico-chimiques de l'eau de surface ainsi que celle souterraine. Les résultats obtenus montrent que les différents paramètres : la demande biologique en oxygène, la demande chimique en oxygène ainsi que les concentrations en nitrate et nitrite présentent des valeurs trop élevées par rapport aux normes   internationales dans plusieurs échantillons analysés. Cette contamination, s’accentue par les activités humaines et les conditions climatiques de la région qui se caractérisent par des débits des oueds très faibles durant la saison d’été. S’ajoute à cela le déversement de la totalité deseffluents urbains et industriels dans les cours d’eau sans traitement préalable. Ceci a pour conséquence d’augmenter les concentrations de polluants déversés dans les cours d’eau entraînant alors une dégradation de la qualité des eaux superficielles et souterraines.Mots-clés : qualité de l’eau, DCO, DBO5, polluants

    Instanton-Meron Hybrid in the Background of Gravitational Instantons

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    When it comes to the topological aspects, gravity may have profound effects even at the level of particle physics despite its negligibly small relative strength well below the Planck scale. In spite of this intriguing possibility, relatively little attempt has been made toward the exhibition of this phenomenon in relevant physical systems. In the present work, perhaps the simplest and the most straightforward new algorithm for generating solutions to (anti) self-dual Yang-Mills (YM) equation in the typical gravitational instanton backgrounds is proposed and then applied to find the solutions practically in all the gravitational instantons known. Solutions thus obtained turn out to be some kind of instanton-meron hybrids possessing mixed features of both. Namely, they are rather exotic type of configurations obeying first order (anti) self-dual YM equation which are everywhere non-singular and have finite Euclidean YM actions on one hand while exhibiting meron-like large distance behavior and carrying generally fractional topological charge values on the other. Close inspection, however, reveals that the solutions are more like instantons rather than merons in their generic natures.Comment: 33pages, Revtex, typos correcte

    Finite energy/action solutions of p1p_1 Yang-Mills equations on p2p_2 Schwarzschild and deSitter backgrounds for dimension d≥4d \ge 4

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    Physically relevant gauge and gravitational theories can be seen as special members of hierarchies of more elaborate systems. The Yang-Mills (YM) system is the first member of a hierarchy of Lagrangians which we will index by p1p_1, and the Einstein-Hilbert (EH) system of general relativity is the first member of another hierarchy which we index by p2p_2. In this paper, we study the classical equations of the p1=1,2p_1 = 1,2 YM hierarchy considered in the background of special geometries (Schwarzschild, deSitter,anti-deSitter) of the p2=1,2,3p_2=1,2,3 EH hierarchy. Solutions are obtained in various dimensions and lead to several examples of non-self-dual YM fields. When p1=p2p_1=p_2 self-dual solutions exist in addition. Their action is equal to the Chern-Pontryagin charge and can be compared with that of the non-self-dual solutions.Comment: LaTeX, 25 pages, 2 figures, new title, minor change

    Yang-Mills Solutions on Euclidean Schwarzschild Space

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    We show that the apparently periodic Charap-Duff Yang-Mills `instantons' in time-compactified Euclidean Schwarzschild space are actually time independent. For these solutions, the Yang-Mills potential is constant along the time direction (no barrier) and therefore, there is no tunneling. We also demonstrate that the solutions found to date are three dimensional monopoles and dyons. We conjecture that there are no time-dependent solutions in the Euclidean Schwarzschild background.Comment: 12 pages, references added, version to appear in PR

    Analysis of Static Bending of Plates FGM Using Refined High Order Shear Deformation Theory

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    This work deals with the analysis of the mechanical bending behavior of a rectangular plate simply supported on four sides (FGM), subjected to transverse static loading. The high order theory is used in this work, The developed models are variably consistent, have a strong similarity with the classical plate theory in many aspects, do not require correction to the shear factor, and give rise to variations transverse shear stresses such as transverse shear parabolically varies across the shear thickness and satisfies surface conditions without stresses. Equilibrium equations are obtained by applying the principle of virtual works. The mathematical expressions of the arrow, the stresses are obtained using Navies approach to solve the system of equilibrium equations. The influence of mechanical loading and the change of the parameter of the material on mechanical behavior of the plate P-FGM are represented by a numerical example

    Dynamical algebra and Dirac quantum modes in Taub-NUT background

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    The SO(4,1) gauge-invariant theory of the Dirac fermions in the external field of the Kaluza-Klein monopole is investigated. It is shown that the discrete quantum modes are governed by reducible representations of the o(4) dynamical algebra generated by the components of the angular momentum operator and those of the Runge-Lenz operator of the Dirac theory in Taub-NUT background. The consequence is that there exist central and axial discrete modes whose spinors have no separated variables.Comment: 17 pages, latex, no figures. Version to appear in Class.Quantum Gra

    EFFECT OF SALINITY ON THE PHYSIOLOGICAL BEHAVIOR OF THE OLIVE TREE (VARIETY SIGOISE

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    Salinity is a major problem directly affecting the ecological balance and the development of agriculture in the Mediterranean basin, particularly North Africa. This phenomenon is considered as the most important abiotic factor limiting crops growth and productivity, degrading and polluting soils in arid and semi-arid. In order to study the influence of salinity, on the physiological parameters and to assess the potential of adaptation of the olive tree in a saline environment, three parcels containing the Sigoise variety and subject to different degrees of salinity were selected: Parcel 1 (non-saline); Parcel 2 (saline); Parcel 3 (very saline). Under a saline constraint, the results showed two contrasting tendencies, an intense increase in the content of proline, sodium (Na+) and chlorophyll (b), while water content, potassium and chlorophyll (a) decreased strongly with increasing salinity

    Détermination des modalités de recharge des aquifères par le biais des traceurs chimiques et isotopiques. Cas de la zone de contact Haut Atlas occidental – Plaine du Souss (SW du Maroc)

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    Determination of the origin of recharge of the unconfined aquifer in the right side of the Souss wadi between Agadir and Taroudant (South-western of Morocco) was based on the use of hydrochemical and isotopic analysis of groundwater, surface water and springs of the contact zone between the High-Atlas Chain and the Souss plain.The correspondence in the space evolution of the various chemical elements of evaporitic origin (SO42-, Cl-, Sr2+) in groundwater, piedmont springs, and surface water reveals the existence of recharge water from the adjacent High-Atlas Chain.The various recharge modes of the different aquifers (High Atlas and Souss plain) determined by isotopic analysis, shows that the source of groundwater for the unconfined Souss aquifer seems to be composite between a direct infiltration on the High-Atlas tributaries and a remote recharge from the bordering High Atlas aquifers.La determinación del origen de los aportes de agua de la capa freática de la ribera derecha del rio Souss entre Agadir y Taroudant (Suroeste de Marruecos) se ha basado en la hidroquímica y el análisis isotópico de las aguas subterráneas, aguas superficiales y manantiales de la zona de contacto entre el Alto Atlas y la llanura de Souss.La correspondencia en la evolución espacial de los diferentes elementos químicos de origen evaporítico (SO42-, Cl-, Sr2+) en las aguas subterráneas, manantiales de pie de monte y aguas superficiales, revela la existencia de una recarga de agua procedente de la cadena del Alto Atlas. El análisis de los modos de recarga de los diferentes acuíferos (Alto Atlas y llanura de Souss) determinado por análisis isotópico, demuestra que la alimentación de la capa freática de Souss a partir del Alto Atlas parece ser mixta, compuesta por una infiltración directa de los afluentes del Alto Atlas y una alimentación lejana desde los acuiferos que limitan con el borde del Alto Atlas
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