1,749 research outputs found
Developing cross‐cultural communicative competence via computer‐assisted language learning: The case of pre‐service ESL/EFL teachers
Based on a qualitative research project, this article presents a view on the use of computer technology to develop a critical cross‐cultural communicative competence in English as a Second Language (ESL) / English as a Foreign Language (EFL) for pre‐service teachers. The article includes a brief critical theoretical framework, some classroom pedagogical implications, and a data‐based discussion of pre‐service teachers’ views. These views included: (1) critical views and an awareness of cultural power relations in computer‐assisted language learning (CALL), (2) uncritical views and a lack of awareness of cultural power relations in CALL, and (3) uses of metaphors in CALL. The powerful contribution of CALL can be found in its potential for providing ways to connect people and build communities, for offering opportunities for cross‐cultural communicative competence to be developed and used, and for improving processes of democratization via computer‐mediated communication. However, a socio‐cultural criticism revealed that this powerful tool, like any other media, is non‐neutral because it can serve to reinforce further the hegemonic aspects of education, that is, the dominant culture will be strengthened and protected via computer technology. Computer‐based technologies and software are increasingly incorporated into the curricula of ESLIEFL teacher education programmes. However, this integration is often done in ways that seem to leave unquestioned the potential cultural and hegemonic ramifications of such technology. Hence there is a need for a more critical technological competence
Reduction of acoustic feedback oscillations by use of spectrum shifting
The problem of whistling noise or self-oscillation in public address systems operating in closed halls or rooms can be very disturbing to the listeners. This noise is sustained when the positive acoustic feedback, of the public address-room system, meets the oscillation criteria. This feedback system results from the acoustic sound signal reflected off the room walls and any other obstacles in the room, originating from the public address speakers and then re-entering the microphone.
When all of the audio signal components entering the public address system are shifted by a frequency increment Δf of 6 Hz, an increase of 5 dB in the useable signal level was achieved and whistling noise reduction is attained.
This thesis describes an apparatus for frequency shifting by small increments in steps of 1 Hz. The system is of simple implementation and effectively reduces the whistling noise and increases the value of achievable gain without introducing any speech distortions.
While the idea turned out to be not original, since it was described in the early sixties, the time for it may be now, because integrated circuits made it feasible in terms of cost, size and portability. Due to this, we feel that reintroducing the idea at this time may be fortuitous
Essai d'analyses quantitative, qualitative et biogéographique de la flore fu Bou-Naceur (Moyen-Atlas oriental, Maroc)
Essai d'analyses quantitative, qualitative et biogéographique de la flore du Bou-Naceur (Moyen-Atlas oriental, Maroc). En l'absence d'étude exhaustive sur le Moyen-Atlas oriental, la flore de cette région est restée assez mal connue par rapport au reste du Maroc. Des recherches sur la flore et la végétation ont été intéressantes sur le massif du Bou-Iblane proche du massif du Bou-Naceur. Mais ce dernier est resté jusqu'à présent moins étudié sur le plan botanique. L'inventaire floristique du Bou-Naceur actuellement évalué à 557 espèces et sous-espèces paraît bien important eu égard à la surface trop restreinte du massif. Dans cet article, nous rappelons brièvement le bioclimat du Bou-Naceur et nous mettons en lumière les récentes connaissances de sa flore et de sa biogéographie
Electron emission from nanostructured materials.
In this dissertation, standardized methods for measuring electron emission (EE) from nanostructured materials are established. Design of an emitter array platform, synthesis and nanomanipulation of different types of are successfully conducted. Preexisting as well as novel nanostructures are examined for possible use as electron point sources. Three main categories of emitters are under evaluation: oxide nanowires, metallic nanowires and carbon based nanomaterials (CBNs). Tungsten oxides nanowires have low work function, then metallic nanowires have high electrical conductivity and abundant number of free electrons at and below their Fermi level and lastly, CBNs have superior electrical, mechanical, chemical and thermal properties. This evaluation is designed to compare and choose among the nanoemitters that are suitable for EE. Simulation through theoretical modeling is provided to optimize the parameters directly or indirectly affecting EE properties. The models are to enhance the emitter\u27s performance through increase the packing density, reduce the field screening effect, lower the turn-on and the threshold electric fields and increase the emission current densities. The current estimations and the modeling of the validity regions where EE types theoretically exist, help to select and fabricate optimum emitters. An assembly consisting of sample substrate, electrical feedthroughs, electrodes, nano/micro-manipulator and insulators are mounted within a vacuum chamber. An ion vacuum pump and a turbo pump are used to reach a vacuum pressure of 10?7 Torr. Two systems are used for EE characterization of nanostructures: bulk and In-situ configurations. The bulk investigation is realized by designing a vacuum chamber and different sample holders that can resist harsh environment as well as high temperature for both FE and TE experiments. In-situ experiments are conducted in the chamber of the scanning electron microscope (SEM), it consists of designing special sample holders plus modifications of the SEM chamber for the ease of EE characterization. Samples with different materials, densities, radii of curvatures, and lengths ranging respectively from 107-10? emitter/cm², 5-300 nm, and 3*10³-107 nm, are produced. The CBNs used are characterized by different structures and shapes that are defined by the monolayer carbon sheet takes. Cylindrical sheets are equivalent to nanotubes while graphene are flat sheets. Emitter\u27s structures are varied by altering the critical growth parameters such as temperature, pressure and constituent materials. Enhancement of the FE properties, the design of an optimum emitter density ad reduction of the field screening effect is possible by selecting appropriate materials, synthesizing nanostructures with small radius (10 nm), high aspect ratio (greater than 1000), the ideal density where the inter-emitter distance is comparable to the emitter height, the cathodes\u27 uniformity, the treatment of the emitting surface, and integrating triode arrangement. Initially, the thermionic Emission (TE) investigations of these nanostructures produce emission at an onset temperature of 500° C, current densities of 160 mA/cm² at temperatures of 700-1200°c and predict the work function of the emitting materials. In addition, nanostructures can enhance the local electric field and increase the packing density to produce better EE properties. Then, FE investigations from different nanostructures showed that the small tip\u27s diameter, high aspect ratio and tapered structures enhance emission through low turn-on fields (0.8 V/µm), low threshold fields (3 V/µm) and high current densities (520 mA/cm²). CCNTs having inter-emitters distance comparable to their average height contribute to the reduction of the field screening effect through large field enhancement factor ß (7000) and enhancement of the EE properties. EE experimental data along with its analysis demonstrate that CBNs have lower turn-on electric field, lower threshold fields, higher current density and higher field enhancement factor than those of microscopic metallic cathodes and oxide nanowires. Therefore, nanomaterial based emitters with their superior intrinsic properties based on the achieved EE results can be turned into potential EE point sources
La production scientifique diffusée dans la revue Al Awamia : une analyse de citations
The agronomic literature diffused in Al Awamia journal can be studied bibliometrically by using the technique of citiation analysis. This important journal publishes the whole results of research undertaken by the National Institute of the Agronomic Research (Morocco). The references cited in the articles of the journal are studied in order to determine, on the one hand, the principal sources of information of the most productive authors by using the model of Bradford and, on the other hand, some characteristics of these sources (support typology and age)
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