Thèses et Mémoires

Contrôle et continuité de fonctionnement du moteur asynchrone à l’aide de la carte DSPACE 1104.

2026-02-11T10:43:23Z

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.

La décision et le manuel opératoire de la césarienne chez la vache. A propos de cinq cas.

2026-02-11T10:24:25Z

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.

Investigation phytochimique et biologique de la propolis Algérienne.

2026-01-27T14:37:49Z

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.

Formulation, fabrication et caractérisation de fromages frais aux laits de dromadaire et de chèvre.

2026-01-27T14:10:37Z

Formulation, fabrication et caractérisation de fromages frais aux laits de dromadaire et de chèvre. Bouras, Biya; Aissaoui Zitoun ép Hamama, Ouarda This study aims to improve the coagulation of camel milk for the production of fresh cheese by using goat's milk and various rennet substitutes. First, we studied the raw materials used, including the raw composition of camel and goat milk and the characteristics of camel rennet, goat rennet and chicken pepsin. Then, we studied the optimization of flocculation and coagulation parameters mainly pH and temperature with milk alone and camelgoat milk mixed with different formulations using response surface methodology (RSM). The optimum points obtained will be used for the manufacture of fresh cheese with enzymatic coagulation and with mixed coagulation by adding mesophilic lactic bacteria. The chemical and mineral analysis of camel milk and goat milk showed the specificity of the composition of camel milk in comparison with cow milk mainly in terms of protein, fat and total solids, lactose and even in chloride, sodium and copper. On the other hand, the characterization of the enzymatic extracts of camel rennet, goat rennet and chicken pepsin revealed variable protein contents and coagulant activities and good coagulant strength, respectively 1/4166.67, 1/2531.64, 1/6153.85. The optimization of the flocculation and coagulation time made it possible to highlight the specific optimum points according to the enzymatic extract used, the type of milk and the formulation tested. It appears that each enzyme acts differently on the coagulation of milk depending on the pH and the temperature, and even when we are under the same conditions, each enzyme gives a specific coagulum. Overall, the pH ranges from 5 to 6.7 and the temperature from 30°C to 42°C. At the level of the manufacture of fresh cheese, twelve formulations were produced and characterized, according to the proportions of camel and goat milk (75/25, 50/50, 25/75) and the type of enzyme. The best cheese yields of enzymatically coagulated fresh cheeses are those of camel rennet cheese with 19.3±0.9% of the FD25, goat rennet cheese with 13.45±0.5% of the FC25, chicken pepsin cheese with 16.65± 1.0% of FP25 and microbial coagulating agent cheese with 18.3±0.4% of FM50. Most of the cheeses obtained can be classified according to the food codex as soft and semi-fat. In rheological terms, the cheeses produced are quite firm. Cheese gel with camel rennet behaves like a dilating coagulum while those produced with chicken pepsin behave like a pseudoplastic coagulum. Whereas, cheeses produced with goat rennet and microbial coagulant behave as a dilating and pseudoplastic coagulum. This clearly shows the effect of the type of enzyme on the coagulation of the camel-goat milk mixture. In addition, electron microscope observations showed the specificity of each coagulum according to the enzymatic extract tested and according to the proportion of goat milk added to camel milk. The difference is noted in the number and diameter of the pores and the appearance of their compactness. Moreover, the statistical analysis of the amino acid concentration results revealed a significant difference (P<0.05) between most of the different formulations with the dominance in the cheeses of histidine. Finally, the best enzymatically coagulated cheeses according to sensory tests are the FD50, FC75, FP50 and FM25 formulations with an overall acceptability score on a score of 15 from 7.85±2.34 (FM25) to 10.05±3.81 (FC75). Finally, the physico-chemical characterization of the best four mixed coagulation formulations (FD50B, FC75B, FP50B and FM25B) gave cheeses with a total solids content of 25.66±0.5% to 43.55±1.2% and Fat/TS of 30.47±2.7 to 49.85±0.16 with a significant difference (P <0.05) for all parameters analyzed. From a sensory point of view, it should be noted that the addition of ferment has clearly resulted in more characteristic and more appreciated cheeses. The results obtained tend and converge towards the possibility of using camel rennet, goat rennet and chicken pepsin in cheese processing based on camel milk mixed with goat milk, taking into account the specific optimum points for each enzyme and each formulation.