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Residual stress has a significant effect for improving engineering properties for metals .Most of the surface treatments produce compressive residual stress at the metal surfaces, which reduce crack initiation and increasing the metal resistance to fatigue, which is shot peening process. Shot peening is usually used for this purpose for producing plastic deformations of surface of the metal which can lead to creation high residual compressive stresses at metal surface .This research include study the influence of shot peening process on fatigue resistance, surface hardness and surface roughness for low carbon steel (AISI 1008). This process accomplished with different times which were (10, 20 and 30(minutes. The result of the fatigue test showed that the fatigue limit increase when shot peening time increased and the best fatigue limit obtained when shot peening process was carried out at 30 minutes. Results of hardness test showed that surface hardness increased with increase of shot peening time. It can be seen that highest value of surface hardness is obtained from shot peening process at time (30 minutes) which is (235.1 HVN). Results of surface roughness test showed that the surface roughness of metal increased when time of shot peening increased
In this study, new derivatives of Schiff bases of 2-thio-5-aryl-1,3,4-oxadiazole have been synthesized. The structures of these derivatives were characterized from their melting points, infrared spectroscopy and elemental analysis.The Schiff bases derivatives were tested for inhibition of E-coli and were all found to be active.
تم في هذا البحث تحضير مشتقات جديدة من قواعد شف لــ 2- ثايو- 5 – اريل – 4،3،1 – اوكساديازول. حيث تم اختيار المشتق رقم 1 كمادة ابتدائية لتحضير قواعد شف بعد مروره بسلسلة من التفاعلات وصولا الى المشتق 4. تم مفاعلة المشتق 1 مع حامض كلوريد الخليك في وسط قاعدي لتحضير المشتق 2. عومل المشتق 2 مع كبريتات ثنائي المثيل حيث اعطى المشتق 3. ان تفاعل المشتق 3 مع الهيدرازين بوجود الكحول كمذيب اعطى مشتق الهيدرازيد 4. تم مفاعلة المشتق 4 مع عدة انواع من الالديهيدات المختارة ليتم الحصول على مشتقات جديدة قواعد شف من (5-9). تمت دراسة الفعّالية البايولوجية للمشتقات من 5-9 ضد بكتريا القولون وقد وجد بأن لها فعّالية بايولوجية واكثرها فاعلية كان المشتق 8.
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