Background: The high reactivity of hydrogen peroxide used in bleaching agents have raised important questions on their potential adverse effects on physical properties of restorative materials. The purpose of this in vitro study was to evaluate the effect of in-office bleaching agents on the microhardness of a new Silorane-based restorative material in comparison to methacrylate-based restorative material. Materials and method: Forty specimens of Filtek™ P90 (3M ESPE,USA) and Filtek™ Supreme XT (3M ESPE, USA) of (8mm diameter and 3m height) were prepared. All specimens were polished with Sof-Lex disks (3M ESPE, USA). All samples were rinsed and stored in incubator 37˚C for 24 hours in DDW. Ten sample of each material were subjected to

Social reform is the main pillar of the organization of societies. Therefore, all religions and theories were directed to focus on this aspect as the most important element for the development of economic and cultural development. In addition to the analysis and application of the Islamic Sharia, he did not present a theory, but offered real solutions and remedies to the crises in our Arab and Islamic societies alike, despite the criticism directed at him. Z his opinions.<

الخلاصة

تشير نظريات علم اجتماع المعرفة الى ان ظهور مفهوم معين او سقوطه لايتم بمحض الصدفة، بل نتيجة تفاعل مجموعة من العوامل الثقافية والسياسية وحتى الاقتصادية ومن هنا فأن ظهور مفهوم الاثنية كان محصلة عوامل كثيرة خصوصاً بعد ان اصبح موضوع الاثنية في العقود الاخيرة من القرن الماضي وبداية القرن الواحد والعشرين محور نقاش رئيس في ميدان البحث الاجتماعي والسياسي، ليس في

      Social reform is the main pillar of the organization of societies. Therefore, all religions and theories were directed to focus on this aspect as the most important element for the development of economic and cultural development. In addition to the analysis and application of the Islamic Sharia, he did not present a theory, but offered real solutions and remedies to the crises in our Arab and Islamic societies alike, despite the criticism directed at him. Z his opinions.

The purpose of this study is designate quenching and tempering heat treatment by using Taguchi technique to determine optimal factors of heat treatment (austenitizing temperature, percentage of nanoparticles, type of base media, nanoparticles type and soaking time) for increasing hardness, wear rate and impact energy properties of 420 martensitic stainless steel. An (L₁₈) orthogonal array was chosen for the design of experiment. The optimum process parameters were determined by using signal-to-noise ratio (larger is better) criterion for hardness and impact energy while (Smaller is better) criterion was for the wear rate. The importance levels of process parameters that effect on hardness, wear rate and impact energy propertie

In this work, results of a mathematical analysis of the role of workpiece preheating in laser keyhole welding were presented. This analysis considered the steady-state welding as well as certain range of boundary conditions over which preheating effect would be indicated. This work is an attempt to interpret the role of preheating to increase welding depth and perform keyhole welding with high quality using physical and thermal properties of steel alloys.

This study was carried out to find out the effect of germination of broad beans and chickpeas seeds for different periods on their antinutritional factors content ( Trypsin inhibitor and Phytic acid ) and the chemical constituents of germination seeds compared with the control samples (ungerminated seeds) . The results indicated asignificant increase (P<0.05) in crude protein content as germination period proceeded.The highest values of 28.0% and 24.0% were reached on the sixth and fourth day for germinated broad beans and chickpeas respectively, The intial values were 25.6% and 23.5% for control samples, respectively. The content of raffinose,stachyose and verbascose were reduced as germination period proceeded, Stachyose and verbascose we