85 research outputs found
Caractérisation hydrogéochimique des eaux souterraines du complexe aquifère Morsott-Laouinet (Région Nord de Tébessa, Sud-Est algérien)
L’analyse des eaux souterraines de l’aquifère superficiel Plio-Quaternaire, pose à nouveau la question de l’importance des faciès gypso-salifères dans la région de Morsott-Laouinet au Nord de Tébessa dans le Sud Est algérien. Ces faciès sont représentés par des affleurements triasiques en surface et par la présence d’un substratum marno-salifère en profondeur. Les analyses chimiques de la totalité des puits de la région le confirment.La salinité des eaux est très variable et généralement élevée. La conductivité électrique de l’eau oscille entre 1154 μS cm-1 et 23800 μS cm-1 avec une concentration élevée d’amont en aval dans le sens de l’écoulement qui se fait du Sud vers le Nord. Les faciès chimiques extrêmes sont le bicarbonaté calcique et le chloruré sodique avec une prédominance de ce dernier. Les teneurs en chlorures et en sodium pouvant atteindre localement les valeurs respectives de 8145 mg l-1 et 3988 mg L-1. La comparaison de la teneur en chlorures avec le reste des éléments majeurs et le strontium, montre que la salinité des eaux souterraines de la plaine de Morsott-Laouinet possède deux origines possibles : la dissolution-précipitation de la roche aquifère et du substratum et l’échange de base entre le sodium et les éléments qui lui sont semblables.Mots-clés : Trias, aquifère, salinité, saturation, Morsott-Laouinet
Gyro-Chirality Effect of Bianisotropic Substrate On the operational of Rectangular Microstrip Patch Antenna
yesIn this paper, the gyrotropic bi-anisotropy of the chiral medium in substrate
constitutive parameters (ξc and ηc) of a rectangular microstrip patch antenna is introduced in
order to observe its effects on the complex resonant frequency, half-power bandwidth and
input impedance. Numerical calculations and analysis based on the dominant mode are
carried out to show that the latter is directly related to the former. This paper is based on the
Moment Method as full-wave spectral domain approach using sinusoidal basis functions. Two
new results, namely the appearance of the difference (ξc-ηc) and sum (ξc+ηc) of the two
magneto-electric elements are obtained in the electric transverse components and Green
tensor expressions, respectively. These new results can be considered as a generalisation form of the previously published work
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Horn Antennas Loaded with Metamaterial for UWB Applications
YesIn this paper, a conical horn antenna has been designed for Ultra-Wideband ap-plications by loading its section with a metamaterial. The work aims first to compare results obtained by the wavelet-moment method to a simulation performed using HFSS. Secondly the conical horn is loaded with a very thin layer of metamaterial to enhance the radiation pattern and the bandwidth performance of the conical horn antenna and reduce the size of the antenna. The operating bandwidth of the proposed antenna is in the range of 10{13 GHz. The results obtained from HFSS and moment method are in good agreement.Electronics and Telecommunication
Offset Aperture-Coupled Double-Cylinder Dielectric Resonator Antenna with Extended Wideband
YesA compact dielectric resonator antenna for ultra-wideband vehicular communication applications is proposed. Two cylindrical dielectric resonators are asymmetrically located with respect to the center of an offset rectangular coupling aperture, through which they are fed. Optimizing the design parameters results in an impedance bandwidth of 21%, covering the range from 5.9 to 7.32 GHz in the lower-band and a 53% relative bandwidth from 8.72 to 15 GHz in the upper-band. The maximum achieved gain is 12 dBi. Design details of the proposed antenna and the results of both simulations and experiment are presented and discussed
Use of slope failures inventory and climatic data for landslide susceptibility, vulnerability, and risk mapping in souk Ahras region
Slope failures (SF) in mountainous terrain often occur during or after heavy rainstorms, resulting in the loss of life and damage to the natural and/or built environment. Assessing areas susceptible to SF is essential for land use planning in threatened areas. This article presents an didactic basedanalysis of the potential contribution to geo-spatial approaches for predicting SF qualitative exposure in mountainous environment. Its main aim is to assess the impact of the geologic, geomorphic, rainstorms, and anthropogenic factors in the initiation of SF in Zaarouria region. 219 events (1996–2016) were inventoried through images interpretation and field surveys and were compared to the physical parameters of the terrain to give a SF susceptibility index value using a simplified model. Vulnerability and risk maps are also established. The Standard deviation classification was used to delineate various susceptibility, vulnerability and risk zones, namely, nil, low, moderate and high. Field data on SF were employed to evaluate and validate the susceptibility zonation map. The results of this study demonstrate that SF are largely governed not only by geoenvironmental conditions but also by human activities, mainly roads and construction
Spray pyrolysis of CuBi2O4 photocathodes improved solution chemistry for highly homogeneous thin films
Dense, homogeneous CuBi2O4 thin films are prepared, for the first time, by spray pyrolysis.</p
A Grating Monopole Antenna on Metamaterial Using MSRR for DVB-T Application
noThis work presents a novel broadband monopole antenna for digital video broadcastingterrestrial
(DVB-T) application. The proposed antenna consists of a grating patch and a concave
rectangular ground plane with defected ground plane, and the Multiple Split-Ring Resonator
(MSRR). The added part in the ground plane and the meta-material are used to enable the antenna
height reduction for fixed ranges of operating frequency. The antenna can operate from 468 MHz to
894 MHz frequency range corresponding to 62.5% of impedance bandwidth for |S11|<-7.5 dB.
Details of the proposed antenna designs and experimental results of the constructed prototypes are
presented and discussed.The full text cannot be displayed due to the publisher's copyright agreement
Solution processed multilayered BiVO4 photoanodes influence of intermediate heat treatments on the photoactivity
Intermediate heat treatments to at least 350 °C are needed to obtain fully crystalline monoclinic BiVO4 films with tunable thickness from spin coating of successive layers from a precursor solution.</p
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