Situation du criquet marocain "Dociostaurus maroccanusThunb., 1815" par rapport aux différentes espèces acridiennes : morphométrie et capacités de déplacements

La faculté de déplacements par vol des criquets adultes permet aux populations acridiennes de se déplacer sur de grandes distances et de rechercher des habitats dont les caractéristiques répondent le mieux à leurs besoins. Dans le présent travail, nous étudions des traits morphologiques d’un certain nombre d’espèces migratrices et non migratrices de deux sous-familles d’Acrididae (Oedipodinae et Gomphocerinae). Par les mesures de différentes parties du corps des criquets adultes, nous avons pu situer le criquet marocain "Dociostaurus maroccanus Thunb., 1815" par rapport à l’ensemble des espèces étudiées. Cette étude morphométrique, souligne bien la liaison existante entre les capacités des déplacements des criquets et leurs traits morphologiques. Ainsi, on note bien une importante distinction morphologique entre l’espèce migratrice Locusta migratoria et les espèces non migratrices. Dociostaurus maroccanus se montre capable d’effectuer des déplacements importants, mais elle ne peut être migratrice comme Locusta migratoria.Mots-clés : Morphométrie, capacités de déplacements, traits morphologiques, Criquet marocain, espèces migratrices

Corrosion Protection of Mild Steel in Hydrochloric Acid at 308 K using Benzimidazole Derivatives: Weight Loss, Adsorption and Quantum Chemical Studies

For the first time, the investigation and characterization of Benzimidazole derivatives, as a potential corrosion inhibitors for mild steel in acidic aqueous solutions has been reported. The inhibition efficiency was calculated based on the data using weight loss, surface studies and basic computational calculations. The values reported in this manuscript were 80% for P1 and 89 for P2. The adsorption of the inhibitors on the mild steel surface was found to obey the Langmuir’s adsorption isotherm. The results obtained from chemical and theoretical techniques are in good agreement with each other

Imidazo[4,5-b]pyridines as a New Class of Corrosion Inhibitors for Mild Steel: Experimental and DFT Approach

6-Bromo-2-methyl-1H-imidazo[4,5-b]pyridine (P1), was investigated for its adsorption and corrosion inhibition traits for mild steel corrosion in 1.0 M HCl solution. Gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopy methods, were used to test the nature of adsorption and the inhibition effect of P1 on the mild steel in acidic media. It was found that the inhibition efficiency improved with the increase of P1 concentration in the acid solution (1.0 M HCl). The adsorption of P1 favored Langmuir adsorption isotherm. The results of corrosion tests confirmed that P1 could serve as an efficient corrosion inhibitor for the mild steel in 1.0 M HCl solution, yielding a high efficiency and low risk of environmental pollution. The theoretical quantum chemical calculations were in good correlation with the experimental result

Superconductivity in the YIr2Si2 and LaIr2Si2 Polymorphs

We report on existence of superconductivity in YIr2Si2 and LaIr2Si2 compounds in relation to crystal structure. The two compounds crystallize in two structural polymorphs, both tetragonal. The high temperature polymorph (HTP) adopts the CaBe2Ge2-structure type (space group P4/nmm) while the low temperature polymorph (LTP) is of the ThCr2Si2 type (I4/mmm). By studying polycrystals prepared by arc melting we have observed that the rapidly cooled samples retain the HTP even at room temperature (RT) and below. Annealing such samples at 900C followed by slow cooling to RT provides the LTP. Both, the HTP and LTP were subsequently studied with respect to magnetism and superconductivity by electrical resistivity, magnetization, AC susceptibility and specific heat measurements. The HTP and LTP of both compounds respectively, behave as Pauli paramagnets. Superconductivity has been found exclusively in the HTP of both compounds below Tsc (= 2.52 K in YIr2Si2 and 1.24 K in LaIr2Si2). The relations of magnetism and superconductivity with the electronic and crystal structure are discussed with comparing experimental data with the results of first principles electronic structure calculations

Etude chimique et biologique des huiles essentielles de Juniperus phoenicea ssp. lycia et Juniperus phoenicea ssp. turbinata du Maroc

Chemical and biological study of essential oils of Moroccan Juniperus phoenicea ssp. lycia and Juniperus phoenicea ssp. turbinata. The composition of the essential oils of the branches and berries of Juniperus phoenicea (Cupressaceae), J. phoenicea ssp. lycia (plain) and J. phoenicea ssp. turbinata (mountain), obtained by hydrodistillation, collected from Morocco, was analyzed by GC and GC/MS. The yields of essential oils were varying in function of the subspecies and of the part of the plant studied. The essential oils of these tree species are largely dominated by α-pinene and may be an important source of this component of a great interest on the international market. The effectiveness of essential oils from branches of the subspecies lycia against fungi decay wood has also been emphasized

Caractérisation d'une collection de tomates issues de différentes régions du Maroc

Tomatoes are one of the most important crops in Morocco. National tomato production reached 1 231 250 tons in 2019. The sector generates thousands of jobs and is one of the pillars of the country's economy through exports. Hence, it is judicious to search for new varieties with high commercial potential. This study aimed to characterize a collection of four local tomato genotypes (‘Taliouine’, ‘Zagora’, ‘Oufella’ and ‘Cerise or Cherry tomato’) from accessions collected in different regions of Morocco, compared to two commercial genotypes (‘Campbell 33’ and ‘Rio Grande’). The analyses concerned agronomic and growth criteria, sensory criteria and physical and physicochemical criteria (humidity, pH, Brix and color). The obtained results showed a great variability between the studied genotypes. Some genotypes showed interesting performances like ‘Campbell 33’ (number of leaves per branch), ‘Rio Grande’ (number of fruits per plant), ‘Cerise tomato’ (number of fruiting branches per plant) and ‘Taliouine’ (plant height). The three genotypes with the best taste are ‘Campbell 33’, ‘Cerise tomato’ and ‘Oufella’. They also show a high intensity of red color, high skin firmness and high aroma content. Significant variations were also observed for the different physicochemical criteria. Such results will help to identify relevant criteria that can be used for varietal improvement and can also constitute basic criteria to differentiate between tomato accessions.Les tomates sont l’une des cultures les plus importantes au Maroc. La production nationale de tomates a atteint 1 231 250 tons en 2019. Le secteur génère des milliers d’emplois et constitue l’un des piliers de l’économie du pays grâce aux exportations. Il est donc judicieux de rechercher de nouvelles variétés à fort potentiel commercial. Cette étude avait comme objectif la caractérisation d’une collection de quatre génotypes de tomates locales issues d'accessions collectées dans différentes régions du Maroc (‘Taliouine’, ‘Zagora’, ‘Oufella’ et ‘Tomate cerise’), comparée à deux génotypes commerciaux (‘Campbell 33’ et ‘Rio Grande’). Les analyses ont concerné des critères agronomiques et de croissance, des critères sensoriels et des critères physiques et physicochimiques (humidité, pH, Brix et couleur). Les résultats obtenus ont montré une assez grande variabilité entre les différents génotypes étudiés. Certains génotypes ont présenté des performances importantes comme ‘Campbell 33’ (nombre de feuilles par branche), ‘Rio Grande’ (nombre de fruits par plante), ‘Tomate cerise’ (nombre de branches fructifères par plante) et ‘Taliouine’ (hauteur de la plante). Les trois génotypes les mieux appréciés pour leur goût sont ‘Campbell 33’, ‘Tomate cerise’ et ‘Oufella’. Ces derniers montrent une forte intensité au niveau de leur couleur rouge, une peau très ferme et des teneurs élevés en arômes. Des variations significatives ont été également observées pour les différents critères physicochimiques étudiés. De tels résultats aideront à identifier les critères importants qui peuvent être utilisées pour l'amélioration variétale et qui peuvent aussi constituer des critères de base pour différencier entre les accessions de tomates

Hydrodynamique dans les milieux gaz/liquide non-newtoniens, agités mécaniquement, étude de l'hélice à profil mince [HPM] et de la turbine à disque de Rushton

The power consumption is measured for non-newtonian gas-liquid systems. The useful zone situated beyond the flooding point was defined by using the power caracteristics plot and hydrodynamic observations. Correlations were established in dimensional or adimensional form, to estimate the stirrer speed at the flooding point, and the power consumption in the working zone. Those correlations established in a large scale of rheological behaviour, for two kind of impellers in different geometrical ratios and for two tanks for scaling up, are used to compare an axial impeller (the thinny profile propeller) to a radial one (the Rushton's disc turbine)