This study proposes the replacement of the conventional straight absorber by the newly designed longitudinally undulated. Numerical results revealed that the new absorber could dethrone the former for several reasons: Among others, it allows a more homogeneous distribution of concentrated solar radiations on its outer surface (Monte Carlo Ray Tracking results); unlike other techniques which improve the inner heat transfer by increasing simultaneously the load of the absorber and the pressure drop within it, the proposed curved absorber is going to generate in a natural way, without any additional mechanical components, vortices within the main streaming which allowed to increase the heat transfer coefficient of about 63 % with an increase of the pressure drop penalty of about 60 %. On the other hand, it allows a drastic reduction of the size of the solar collector field. All these facts lead to decreasing the wall temperature gradient bellow 40 K. Results are obtained for the Syltherm 800 Reynolds number range 2.5×104 to 12.3×104 and a fluid inlet temperature of 450 K.

The aim of this paper is to perform a keyword analysis in two areas of research: Intellectual Capital and Knowledge Management. The keywords are of three types : keywords proposed by the authors in their articles, the keywords that users use in their queries and the densest words existing in a textual corpus. Zipf’s law usually applied for natural language is applied in this work for scientifc corpus constituted of confused full articles in each area. We wrote 8 R programs going through titles of articles, authors’ keywords, abstracts and full articles to calculate frequencies and interpret them. The keywords of intellectual capital measurement and diclosure have the highest frequencies. The measures are stated by companies in annual reports and could not be integrated in their balance sheets because the classical accounting does not take into acount intellectual capital as an asset. Knowledge management is more oriented towards the capitalization of knowledge to improve business performance and for industries. This work is the first in keyword analysis for the two areas. It could be usefull to prepare glossaries, ontologies and all semantic reasearhes of research areas.

Recently, the Junctionless Double Gate MOSFET with source/drain extensions has proved competitive performance measures due to the reduction of the series resistance between the metal contacts and source/drain regions. However, the precise modeling of different response functions is still an important issue especially at nanoscale level because of the inclusion of complex phenomena such as quantum transport mechanisms and hot carrier degradation effect. In this perspective, our aim in the presented work is to investigate the efficiency of a novel approach based on Kriging metamodeling and multi-objective particle swarm optimization for the exploitation of the considered device in terms of some analog/RF performances. Data generated by ATLAS-2D simulator, are used to establish Kriging metamodels for the Gain and Transconductance Generation Factor. It is highlighted that the obtained models can be used accurately in a multi-objective context to offer several Pareto optimal configurations. As a result, a wide range of biasing configurations is available to the designer depending on imposed constraints.

Les effondrements des cavités souterraines dans les calcaires karstifiés constituent un aléa géologique sérieux qui continue à recevoir une intention particulière à l’échelle de la planète. Il s’agit d’un phénomène très connus, lié à la présence de vides souterrains dans les terrains calcaires, dolomitiques et gypsifères. Le plateau de Chéria correspond à une structure synclinale, grossièrement triangulaire d’orientation NE – SW affecté par une fracturation orthogonale à l‘axe du pli. Il est essentiellement formé de calcaires Eocène largement karstifié et recouvert de matériaux meubles, essentiellement des alluvions, des argiles et des encroutements calcaires. Ce bassin en question abrite trois aquifères superposés, l’aquifère du Maastrichtien, l’Eocène et la nappe alluviale du Moi-Plio-Quaternaire. Celle qui fait l’objet de cette étude est la nappe de l’Eocène. Le sens d’écoulement générale dans les nappes souterraines notamment les alluvions et l’Eocène est sensiblement Nord-Sud. La surexploitation actuelle des eaux souterraines a rendu la nappe des alluvions sans intérêt hydrogéologique, et a causé un grand rabattement dans les calcaires de l’Eocène. Les méthodes directes et indirectes d’explorations du sous-sol de la région ont révélés la présence de plusieurs cavités souterraines de dimensions importantes. La méthode de tomographie électrique, Géoradar et les sondages mécaniques ont montré l’existence à faible profondeur des cavités dans la région d’étude. La stabilité de ces cavités dépend d’un côté des propriétés mécaniques de la masse rocheuse formant le toit de la galerie, et les dimensions de cette dernière. Cette étude nous a permis d’établir des relations entre l’épaisseur du toit, largeur de cavité, et la charge pour un RMR (Rock masse rating) variable. La cartographie menée à l’échelle de la région a pu délimiter les zones susceptibles de présenter des cavités naturelles instables et cela va permet en conséquence de trouver des solutions au problème de l’effondrement à l’échelle de la région