فهرست مطالب masoud mohamadi

During the drilling of the jawbone, the temperature could increase and cause thermal injury in the bone. So, it appears necessary to investigate the temperature rise during bone drilling. Due to the difficulty of experimental study of temperature increase during the jawbone drilling, predicting the heat transferred to the bone during surgery, leads to the correct selection of factors affecting the temperature. Therefore, in this paper, for the first time, using the finite difference method and Wiener coefficients, the temperature of the jawbone during drilling was predicted and the influence of different drilling parameters on the temperature rise was evaluated. Spindle speed were 200, 400, 800, 1200 and 2500 rpm, feed rate 50, 60, 90 and 120 mm/min and drill point angle 70, 90 and 118 degrees. Results showed that an increase in spindle speed and decrease in feed rate caused an increase in bone temperature. Also, with an increase in drill point angle from 70 to 118 degrees, the temperature increases by 10 degrees Celsius. Finally, the following combination of parameter values is suggested: feed rate of 90 to 120mm/min, spindle speeds of 200 to 2500rpm and point angle of 70˚ and 90˚. With irrigation, the decrease in temperature was almost equal to 9˚C.

Bone drilling process is one of the essential steps in orthopedic surgeries. If temperature of this process is more than 47 ° C, thermal necrosis occurs. In the event of the thermal necrosis, bone consolidation is not well done. For this reason, a lot of research has been done to reduce the thermal necrosis. In this study, by using an analytical model, bone temperature elevation during drilling was investigated at different feed rates and rotational speeds. To validate the analytical results, the bone temperature elevations were evaluated by comparison with bone drilling process using bovine femurs. With comparison the results, it was found that there are differences between analytical and experimental results that are related to incorrect estimation of the fraction of total heat generated that flows into the bone. Therefore, the correct values of this fraction were obtained after comparing analytical and experimental results. Finally, it was concluded that the fraction is dependent on the feed rate and rotational speed, and also a new equation was presented for it. Experimental results show that within the range of the investigated variables, increase in feed rate causes decrease in bone temperature and with the increase in rotational speed, the bone temperature changes are swinging.

One of the most controversial issues within Iraq and throughout the Middle East is the issue of Iraqi Kurds' independence. The unilateral declaration of independence and the referendum by the KRG in 2017 led to opposition from the Iraqi Administration and neighboring countries, that way the declaration of independence was soon rejected. The present study intends to explain the views of Iraq's neighbors regarding the declaration of independence of the Kurds of Iraq, also the reasons of this opposition and their concerns. Explaining the policies of Russia, the European Union, the United States and Israel towards the independence of the Kurds will also be among the aims of the present study. The findings show that security concerns about the territorial integrity of the region have been the main cause of opposition by these states to the formation of an independent Kurdistan, while other transnational actors have sought to adopt ambiguous positions and take advantage of this issue as a means of securing their national interest. The method of research in this research is analytical-descriptive and the resources are collected in library method.