DES FORMES D’ÉVALUATION POUR LA FILIÈRE « LANGUE FRANÇAISE » EN CONTEXTE UNIVERSITAIRE ALGÉRIEN

L’importance de l’évaluation en tant qu’outil pédagogique est évidente. Quel que soit son objet (apprenants, enseignants ou contenus), elle est indispensable dans n’importe quel processus d’enseignement-apprentissage. Ses fonctions varient du diagnostic d’un état actuel à la remédiation des lacunes pour atteindre un état souhaité en certifiant des acquis. Aux établissements d’enseignement supérieur, les enseignants adoptent des formes d’évaluations différentes. Pour les cerner au sein des classes de niveaux d’étude différents, nous avons mené une enquête par questionnaire auprès d’un groupe d’enseignants de deux universités algériennes. Notre objectif est d’inventorier les formes d’évaluation à ce niveau supérieur en relevant leurs avantages et leurs limites. Les résultats que nous avons obtenus montrent que les enseignants recourent à des évaluations parfois simples (une seule forme) et, dans d’autres cas, combinées (deux formes ou plus)

A Comparative Study of the Performance of Uncoated, PVD, CVD and MTCVD Coated Carbide Inserts in Dry Turning of AISI4140 Steel

An experimental study has been carried out to investigate and compare the cutting tool performances represented by insert wear, surface roughness and cutting forces of an uncoated carbide (H13A) and three coated carbides GC2015 ( TiCN / Al2O3 / TiN ), GC1015 (TiN) and GC4215 ( TiCN / Al2O3 ) during the dry turning of AISI4140 steel. Turning was carried out during 5 minutes on cylindrical specimens (80 mm diameter and 400 mm cutting length) along with a depth of 0.5 mm, a feed rate of 0.08 mm/rev, and with a cutting speed of 350 m/min. The wear results show the effectiveness of both GC2015 and GC4215 cutting inserts where the flank wear rate of the monolayer insert (GC1015) reaches approximately 2 times that of the bilayer insert (GC4215) and 4-times that of the multilayer insert (GC2015), while insert H13A demonstrated the highest wear. Moreover, SEM analysis shows that abrasion, adhesion and chipping are the dominant wear mechanisms. The surface quality obtained with the coated GC2015 insert is found to be 1.38, 1.63 and 4.63 times better than those obtained with GC4215, GC1015 and H13A inserts respectively. Finally, the coated GC2015 (CVD) cutting insert is identified as the leading material in terms of cutting force as the results found show that the ratios are ( Ft-GC4215 / Ft-GC2015 ) = 1.05, ( Ft-GC1015 / Ft-GC2015 ) = 1.13 and ( Ft-H13A / Ft-GC2015 ) = 1.77

Spatial variation of coda wave attenuation in the AL Hoceima region (Earthquakes of 24 Frebruary 2004), Morocco

On 24th February 2004 a significant earthquake (Md = 6.4) occurred in the north of Morocco causing great damage in the vicinity of Al Hoceima region. This area is characterized by a complex faulting system as a result of compressional tectonic forces. Three short period stations are set in this area of interest and recordings from these stations were used in this study. In order to complete our knowledge of attenuation, 60 local earthquakes are recorded a few days after the great earthquake with magnitude Ml 2.6-5.0 to estimate seismic attenuation. For this purpose, we applied the single backscattering model of Aki & Chouet 1975 in the frequency range for 1 to 4 Hz. The study of coda waves was limited to a relatively short lapse time (10 Seconds) in order to sample the earth’s crust only .The values of Qc estimated for all the three stations show a strong frequency dependent relationship of the form Qc=Q0fn, where Q0 is Qc at 1Hz , and n represents the degree of frequency dependence , and reflect the level of crustal heterogeneities to varying degrees. The average frequency dependent attenuation relationship has been obtained which indicates that the attenuation is high in this region. Finally to conclude our work, the values of Q0 suggest that Al Hoceima area is highly heterogeneous and the n parameter indicates a meaning frequency dependence of Qc

Estimating porosity and density of calcarenite rocks from P-wave velocity

Petrophysical proprieties such as porosity, density, saturation have a marked impact on acoustic proprieties of rocks. Hence, there has been recently a strong incentive to use new geophysical techniques to invert such properties from seismic or sonic measurements for rocks characterization. The P-wave velocity, is non-destructive and easy method to apply in both field and laboratory conditions, has increasingly been conducted to determine the geotechnical properties of rock materials. The P-wave velocity of a rock is closely related to the intact rock properties and measuring the velocity in rock masses describes the rock structure and texture. The present work deals with the use of simple and non destructive technique, ultrasonic velocity to predict the porosity and density of calcarenite rocks that is characteristic in historical monument. The ultrasonic test is based on measuring the propagation time of a P-wave in the longitudinal direction. Good correlations between P-wave velocity, porosity and density were found, which indicate them as appropriate technique for estimating the porosity and density

Quality factor of seismic coda waves from earthquakes in northern Morocco

The main objective of this work is to analyze seismic attenuation (1/Qc) using a single backscattering model hypothesis of Aki and Chouet (1975). For this purpose, the recordings of 66 local earthquakes (epicentre distance < 100 km) during 2008 in Northern Morocco have been used with a magnitude (Ml ) less than 4. The Qc quality factor values have been computed at four central frequencies 0.75, 1.5, 3, 6 and 12 Hz and analyzed for two horizontal and vertical components for performing the average values. Four lapse time windows seconds from 30 to 60 duration with a difference of 10 seconds have been analyzed to study the lapse time dependence of Qc. We obtained a strong average frequency dependence follow a power law Qn=Q0fn where Q0 is Qc at 1Hz and n is the power of frequency dependent .The frequency dependent relationships obtained are Qc=(143.75±1.09)f(0.864±0.006) for the vertical component , Qc=(149.12±1.08)f(0.85±0.05) and  for the N component , and Qc=(140.42±1.81)f(0.902±0.04) for the E component. The values estimated of coda Q shows independent on the component of wave motion consistent with (Jen-Kuang Chung 2009 and Priyamvada Singh 2012 ), thus only one component sufficient to treat the attenuation in this region. The mean values of the estimated Qc of the vertical component vary from 76 (at 0.75) to 1147.6 (at 12 Hz) for 30  seconds coda window length, for 40 seconds coda window length Qc vary from 122.48 (at 0.75) to 1255 (at 12 Hz ) while for 50 seconds coda window length Qc vary from 141.4 (0.75) to 1420.8 (at 12 Hz ) . Similarly for 60 seconds coda window length Qc vary from 173.89 to 1495. The increase in Qc values with lapse time shows the depth dependence which agree with many studies. The results obtained with this model are presented and then compared to results from the literature

Transport equation for growing bacterial populations (II)

This article studies the growing bacterial population. Each bacterium is distinguished by its degree of maturity and its maturation velocity. To complete the study in [3], we describe the bacterial profile of this population by proving that the generated semigroup possesses an asynchronous exponential growth property