http://depot.umc.edu.dz/handle/123456789/1 Mon, 20 Jul 2026 07:57:33 GMT 2026-07-20T07:57:33Z http://depot.umc.edu.dz/handle/123456789/14840 Contribution à l'élaboration de l'oxyde de titane par le procédé sol-gel Bouachiba, Yassine; Bouabellou, Abderrahamane The present work consists in the elaboration and the characterization of TiO2 thin films by sol-gel method. Particular attention is paid to the influence of temperatures, the annealing atmosphere, the thickness, the nature of the substrates and doping with Fe element on the different structural, morphological, optical, dielectric and chemical properties. The different samples are characterized by the X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy, FTIR spectroscopy, spectroscopic ellipsometry, UV-Visible spectroscopy, m-lines spectroscopy and hydrophilic measurements. The structural study shows that the crystallization of the films occurs for critical thicknesses. The thermal annealing under various atmospheres (air and oxygen) and the presence of buffer layers between the TiO2 film and the substrate are important factors affecting the formation and improving the structure of anatase and rutile phases. The phase transformation anatase-rutile occurs at high temperature (800°C). The SnO2 interfacial layer and the high doping level (7% at.) have the effect of decreasing the temperature of this transformation. The morphological study shows, in general, a uniform growth with relatively low roughness, which bodes the optical quality of the films obtained. The optical study shows that the values of the refractive indices derived using the sem-infinite, Fourouhi-Bloomer and EMA models are in good agreement with those of the literature. The study of the optical gap obtained by spectroscopic ellipsometry and the UV-visible spectroscopy reveals some variation depending on various parameters. The waveguiding measurements show that TiO2 films deposited directly on the glass behave as single-mode waveguides in the two polarizations (TM and TE). When SnO2 and ZnO films are used as buffer layers, we note the disappearance of TM modes. The dielectric study shows that the approach based on the Kramers-Kronig analysis and Maxwell's equations is proved acceptable in comparison with other known models. The analysis of wetting water shows the super-hydrophilicity of TiO2/verre and TiO2/(ZnO/glass) samples. Thu, 08 May 2014 00:00:00 GMT http://depot.umc.edu.dz/handle/123456789/14840 2014-05-08T00:00:00Z http://depot.umc.edu.dz/handle/123456789/14832 Contrôle et continuité de fonctionnement du moteur asynchrone à l’aide de la carte DSPACE 1104. Bouabid, Nourelhouda; Khezzar, Abdelmalek This work provides a new diagnosis method for broken bar and mixed air gap eccentricity faults in the closed loop control of a squirrel cage induction motor. The closed loop system is widely used in industrial applications due to the efficiency of the variables of the regulator outputs for diagnosis because it directly shows the action of the control. The regulator will continue to force the controlled variables to the reference value, resulting in a decrease in the magnitude of the diagnostic indicators and a loss of information critical for detecting faults that cause a motor disaster. This work Based on the direct stator current fault signature as well as the speed fault signature to return the real magnitude of the fault diagnosis indices without affecting the indirect field control. Furthermore, the real magnitude is used to compensate for the fault magnitude and to obtain a machine operating in a healthy state. Using the discrete Fourier transformation. The transfer function is utilized to find the analytical expression of the measured electrical and mechanical parameters at both conditions. The fault signature and error of the torque are used to compensate for the fault signature speed, torque, and quadrature stator current. The simulation and experiment results are included to verify the effectiveness of the theoretical analysis. Wed, 29 Nov 2023 00:00:00 GMT http://depot.umc.edu.dz/handle/123456789/14832 2023-11-29T00:00:00Z http://depot.umc.edu.dz/handle/123456789/14831 La décision et le manuel opératoire de la césarienne chez la vache. A propos de cinq cas. Medjguer, Sihem; Bensegueni, Abdellatif In the first theoretical part, the study makes callbacks on the anatomy and physiology of parturition of cow that will be the key to the success of the surgical Act, emphasizing the indications that were causes of dystocia calving requiring a cesarean-section. The second part reports five cases of caesarean section in professional practice representing the bovine medical propaedeutic, which forms the basis of the diagnostic approach, describes the results and gives recommendations. Sun, 01 Jan 2017 00:00:00 GMT http://depot.umc.edu.dz/handle/123456789/14831 2017-01-01T00:00:00Z http://depot.umc.edu.dz/handle/123456789/14830 Investigation phytochimique et biologique de la propolis Algérienne. Daikh, Amina; Segueni, Narimane Our study is interested in the investigation of the chemical composition and the biological activities of Algerian propolis. In the first part of our study we examined several propolis harvested from Algerian East in order to compare their antibiofilm and cytotoxicity activities, In addition, the UPLC-ESI-MS/MS analysis of the most active extracts was also evaluated. In the second part we studied the antioxidant capacity of two other propolis by five different methods. The total phenolic and flavonoid contents were evaluated. Propolis of Mila exhibited the highest antioxydant activity. This result encouraged us to study the cytotoxicity activity of the extracts of this propolis. This propolis acts on MDA-MB- 231 cells by inducing apoptosis by increasing the concentrations of Bax, caspase 3 and p53 proteins as well and decreasing Bcl2 and CDK-4 proteins. These results are confirmed by the study of mRNA and cDNA. In the last part of our work we were interested in the chemical composition of Algerian propolis. After extraction, separation and purification, we obtained 6 pure flavonoids 5,4'-dihydroxy-6,7-dimethoxyflavone (Cirsimaritine), 7-methoxy 3,5 dihydroxyflavonol (Galangine 7-methoxy), 4',5,7-trihydroxy-3-methoxyflavone (isokampferide), 5,7-dihydroxy-flavanone (Pinocembrine), Apigenin 7-methoxy (Genkwanin) and Apigenin. Our study demonstrated that all the studied propolis are probably of t poplar type. Thu, 07 Dec 2023 00:00:00 GMT http://depot.umc.edu.dz/handle/123456789/14830 2023-12-07T00:00:00Z