Bexi I.,CNRS Paris Institute of Global Physics |
Bexi I.,University Of Djibouti |
Chavanne X.,CNRS Paris Institute of Global Physics |
Conejo E.,CNRS Paris Institute of Global Physics |
Frangi J.-P.,CNRS Paris Institute of Global Physics
IEEE Transactions on Instrumentation and Measurement | Year: 2012
This paper describes the procedure to qualify an admittance meter as a permittivity meter and a conductivity meter sensor through validation with liquids over a range of relative permittivity r values from 1 to 80 and with operating frequencies f between 1 and 20 MHz. The sensor is a capacitor which consists of two parallel cylinders of 10-cm typical dimension. A circuit-based model of the sensor was previously calibrated against accurate electronic components. A discrepancy of 10% is found between the calibration with components and the validation with liquids. All potential errors have been carefully examined: parasitic impedances of the electronic circuit and leads, modifications of liquid permittivity rliq due to temperature influence, water contamination or relaxation effects, and possible fringing effects with the help of numeric simulations. Forty percent of the discrepancy results from the finite dimensions of the liquid-filled recipient. The fringing effects due to insulating rings at each end of the capacitor seem to be discarded. The analysis of the uncertainty on r sensor and ; sensor shows a relative uncertainty of 3%-5% due in large part to the numerical acquisition of high frequency. © 2012 IEEE.
Abdoul-Latif F.M.,University Of Djibouti |
Abdoul-Latif F.M.,University of Ouagadougou |
Mohamed N.,Center Detudes Et Of Recherches En Biotechnologie |
Edou P.,Mohammed V University |
And 6 more authors.
Journal of Medicinal Plants Research | Year: 2011
The essential oil and methanol of Matricaria Chamomilla L. were subjected to screening for their possible antioxidant activity by two complementary test systems, namely 2,2-Diphenykpicrylhydrazyl (DPPH) free radical scavenging and β-carotene-linoleic acid assays. BHT was used as positive control in both test systems. In the DPPH test system, the IC50 value of essential oil and methanol extract were respectively 4.18 and 1.83 μg/ml. In the β-carotene-linoleic acid system, oxidation was effectively inhibited by M. Chamomilla, the RAA value of essential oil and methanol extract were respectively 12.69 and 11.37%. When compared to BHT, the oil and methanol extract were nearly the same value. The essential oil and methanol extract were tested against bacterial and fungal strains using a broth microdilution method. The results suggest that M. Chamomilla, oil and methanol extract have significant antimicrobial activity. © 2011 Academic Journals.
Guedi A.O.,University Of Djibouti |
Huchard M.,Montpellier University |
Miralles A.,IRSTEA |
Nebut C.,Montpellier University
Proceedings - IEEE International Enterprise Distributed Object Computing Workshop, EDOC | Year: 2013
The design of class models for information systems, databases or programming is a delicate process in which experts of the domain and designers have to identify and agree on the domain concepts. Formal Concept Analysis (FCA) has been proposed for supporting this collaborative work and fostering the emergence of higher level entities and the factorization of descriptions and behaviors. More recently, an extension of FCA, Relational Concept Analysis (RCA), has been designed to extend the scope of FCA to the emergence of higher level domain associations. FCA and RCA build a kind of normal form for models, in which the factorization is exhaustive, and the specialization order is adequate. The counterpart of these strong properties is a worst-case exponential theoretical complexity. In this paper, we study a practical application of RCA on several versions of a real class model in order to give precise figures about RCA and to detect which configurations are tractable. © 2013 IEEE.
Aaboubi O.,British Petroleum |
Ali Omar A.Y.,British Petroleum |
Ali Omar A.Y.,University Of Djibouti |
Franczak A.,Catholic University of Leuven |
Msellak K.,British Petroleum
Journal of Electroanalytical Chemistry | Year: 2015
In the preliminary paper, devoted to the study of magnetic field effects on the catalytic properties of nickel-molybdenum (Ni-Mo) system for hydrogen evolution reaction (HER), we have shown that the main effect of a magnetic field is related to the deposits surface modifications. In the present paper the electrodeposition kinetics of Ni-Mo was investigated, using electrochemical impedance spectroscopy (EIS) and polarization curves methods with and without magnetic fields. The reaction path was proposed to account for the main features of the deposition kinetics (polarization curves and impedance diagrams). This involves the reduction of Ni(II) and Mo(IV) complexed species into compounds that can be included as a whole into the deposit or decomplexed to product alloys deposits. In both cases the charge transfers reactions occurred in more than two steps, coupled by adsorbed intermediates. The proposed model can also account for the current density dependency upon the potential value and the magnetic field intensity. © 2014 Elsevier B.V. All rights reserved.
Kileh Wais M.,French National Institute for Agricultural Research |
Kileh Wais M.,University Of Djibouti |
Elsen J.M.,French National Institute for Agricultural Research
Journal of Animal Breeding and Genetics | Year: 2012
QTL detection using the regression of phenotypes on transmission probability is largely used when large families are available. In three generations designs, the use of a 'de-regressed proof' as a phenotype to be analysed was proposed by Weller (1990) and Tribout (2008). Our work generalizes this approach. A score (that we define as a 'generalized de-regressed proof') is described, which combines performance phenotypes recorded in multigenerational offspring of genotyped individuals. Estimation of the QTL effect on this score with a simple regression is unbiased. The link between this score and the BLUP animal model of the polygenic effect is demonstrated. The theory is developed and two simple examples illustrate how this technique can be implemented. © 2011 Blackwell Verlag GmbH.