LA VILLE SAHARIENNE ET LES PROBLEMES DE L’ARMATURE URBAINE : CAS DE LA MICRO-REGION DE SIDI OKBA

Aujourd’hui, les villes considérées dans leurs fonctions tertiaires comme centres des activités de services, ne sont pas des organismes indépendants et isolés les uns des autres. Cependant, la répartition inégale de ces services peut, d’une manière générale, déséquilibrer le système urbain. La hiérarchie urbaine des centres de la micro-région de Sidi Okba en Algérie est déséquilibrée et les centres qui la composent n’arrivent plus à répondre aux besoins de leurs populations respectives, ce qui met en cause l’état de santé de son armature urbaine. L’objectif de cette recherche est de mettre en exergue la réalité de cette entité spatiale à travers l’évaluation socio-économique et urbaine de ses centres en faisant recours à diverses techniques et à divers modèles d'analyse tels les modèles gravitaires, les modèles à critères multiples, ainsi que l'approche systémique qui considère l'espace comme un tout organisé présentant des éléments de composition inter reliés, inter dépendants et inter actifs

L’IMPLICATION DE LA PLANIFICATION URBAINE DANS LE DESEQUILIBRE DE L’ARMATURE SPATIALE : CAS DE LA MICRO-REGION DE SIDI OKBA

Aujourd’hui, les villes considérées dans leurs fonctions tertiaires comme centres des activités de service, ne sont pas des organismes indépendants et isolés les uns des autres. Cependant, la répartition inégale de ces services peut, d’une manière générale, déséquilibrer le système urbain. La hiérarchie urbaine des centres de la micro-région de Sidi Okba en Algérie est déséquilibrée et les centres qui la composent n’arrivent plus à répondre aux besoins de leurs populations respectives, ce qui met en cause l’état de santé de son armature urbaine. L’objectif de cet article est de mettre en exergue la réalité de cette entité spatiale à travers l’évaluation socio-économique et urbaine de ses centres en faisant recours à diverses techniques et à divers modèles d'analyse tels les modèles gravitaires, les modèles à critères multiples, ainsi que l'approche systémique qui considère l'espace comme un tout organisé présentant des éléments de composition inter reliés, inter dépendants et inter actifs.اليوم، إن المدن التي تعتبر وظائف قطاعها الثالث كمراكز لأنشطة الخدمات ليست مستقلة ومعزولة عن بعضها البعض. غير أن التوزيع غير المتكافئ لهذه الخدمات يمكن، بوجه عام، أن يؤدي إلى عدم توازن النظام الحضري. إن التسلسل الهرمي الحضري لمراكز منطقة سيدي عقبة في الجزائر غير متوازن ولم تعد المراكز التي تكونها قادرة على تلبية احتياجات سكانها، الأمر الذي يشكك في حالة صحة هيكلها الحضري. الهدف من هذا المقال هو تسليط الضوء على واقع هذا الكيان المكاني من خلال التقييم الاجتماعي والاقتصادي والحضري لمراكزه باستخدام مختلف التقنيات ونماذج التحليل مثل نماذج الجاذبية والنماذج والنهج المنهجي الذي يعتبر الفضاء ككيان منظم مع عناصر مترابطة ومتشابكة ومترابطة فيما بينها

An Optical Boundary Scan Cell for On Line Testing of Embedded Systems

International audienc

Error Analysis of a Rotating Quarter-Wave Plate Stokes' Polarimeter

NRC publication: Ye

Indoor Pedestrian Localization With a Smartphone: A Comparison of Inertial and Vision-Based Methods

International audienc

Indoor Pedestrian Localization With a Smartphone: A Comparison of Inertial and Vision-Based Methods

International audienc

New organic-inorganic hybrid ionic material Tris(melaminium) monodrogenphosphate dihydrogenphosphate tetrahydrate: synthesis, single-crystal structure, Hirshfeld surface analysis, spectroscopic characterization, and thermal behavior

International audienceA novel type-I hybrid ionic material named Tris (melaminium) monodrogenphosphate dihydrogenphosphate tetrahydrate (3C3H7N6+.HPO42−.H2PO4−.4H2O) was synthesized. Its structure was affined by single crystal X-ray diffraction, illustrating that the material crystallizes in P1− triclinic system with cell parameters a = 11.2424(9)Å, b = 11.8460(9)Å, c = 11.983(9)Å, α = 66.929(3)°, β = 71.555(3)° and γ = 64.303(3)° and a filling rate Z = 2. The 3D-supramolecular network is constituted by non-stacked planar melaminium chains, laid along a diagonal direction of the unit cell, and joined indirectly via the inorganic part's molecules, forming lamellar material along Oc-direction; the various contacts were discussed through 3D-Hirshfeld surface analysis. The UV–visible spectroscopy reveals that this hybrid material is transparent in the visible and UV near visible domains, and has considerable absorption in middle and far UV. The several vibration modes were analyzed by FT-IR spectroscopy and correlated to the functional groups of the affined structure. The thermal decomposition behavior was studied by TGA/DTG and DSC techniques exhibiting a good thermal stability of 340°C

Extraction of phenolic compounds from Vitex agnus-castus L.

The primary objective of this study was to valorize Vitex agnus-castus residues in terms of phenolic compounds with antioxidant activity. The effects of extraction time (30-360 min), solid to liquid ratio (0.1-0.3 gDryBiomass/mlSolvent), type of solvent (methanol or ethanol) and different tissue types (leave, roots and seeds) on total polyphenols, o-diphenols, total flavonoids and anthocyanins were evaluated. The highest total polyphenol (31.5 mgCaffeicAcidEquivalent/gDryBiomass) and o-diphenol (12.4 mgCaffeicAcidEquivalent/gDryBiomass) contents were obtained from methanolic extract of leaves after 180 min using a solid/liquid ratio of 0.1 gDryBiomass/mlSolvent, while total flavonoids, reached a maximum value of 19.4 mgCatechinEquivalent/gDryBiomass after 360 min under the same conditions. Roots of Vitex agnus-castus were found to be a good source of anthocyanins with the highest yield of 0.62 mgMiricetinEquivalent/gDryBiomass using ethanol as a solvent (180 min and 0.2 gDryBiomass/mlSolvent). The maximum antiradical power (178.5 \ub5lextract/\ub5gDPPH) was exhibited by the methanolic leave extract obtained after 360 min at solid/liquid ratio of 0.3 gDryBiomass/mlSolvent

Effect of UV radiation and titanium dioxide on polyphenol and lipid contents of Arthrospira (Spirulina) platensis

Phenolics and lipids of Arthrospira (Spirulina) platensis are important compounds with attractive properties. The influence of two oxidative stress conditions (UV irradiation and TiO2 concentration) on the production of these added-value compounds was investigated. UVand TiO2 stresseswere shownnot to influence the final concentration of biomass that resulted to be 4.83 and 5.08 g L-1, respectively. Compared to the control run, total polyphenol yield decreased by 7.5, 24.1 and 23.1% afterUVexposure for 3, 6 and 9 h, respectively, whereas in the presence of 0.10, 0.25 and 0.50 g L-1 of TiO2 such a yield increased by 8.4, 7.0 and 7.3%, respectively. However, the treatment with 9 h of UV stress led to a lipid content increase of 29.5%, but with a reduction of the FAME fraction (67.3%).While the TiO2 stress lead to a substantial decrease of total lipid fraction. These results on the whole suggest that UV irradiation could be usefully exploited to increase the lipid content of microalgae or cyanobacteria for different applications in bioenergy production (e.g. combustion, gasification and pyrolysis), while the increased phenolic content induced by the oxidative stress with TiO2 may be of some interest in both the pharmaceutical and cosmetic sectors