اکرم خدایاری

In this study, shock wave mitigation technique was analyzed using qualitative observations of plasma discharge in Mach 2.45 and atmospheric conditions testing. Plasma was produced in front of the aero-spike model by a 50 Hz, 50 mA, 30Kv electrical discharge and shadowgraph imaging technique at 300 frame per second and camera recording at 1000fps were used to record the qualitative results. Laboratory results show that increasing the magnetic field increases the frequency, stabilizes the glow discharge, changes the motion path of the charged particles from circular to cyclotron, improves plasma overlapping and also thickens the shock layer. Shadowgraph images at Mach 2.45 show that combining magnetism with and increased by 7.5 degrees at a shock wave angle and mitigates shock waves and removes the bow shock downstream of the spike. This is the most important result that indicates combining plasma and magnetism can remove shock waves at supersonic speeds and thus reduce wave drag.

Shock waves are presented in hypersonic aircrafts. They increase drag and as a result of additional friction, surface heating increases. In this research, a wind tunnel model; a combination of a 60o slender physical spike, used as cathode and a 60o truncated cone- cylinder, as anode, were experimented in flows with Mach numbers 1.5, 1.95, and 2.45. Plasma was produced in front of the aero-spike model by electrical discharge of 50 HZ, 30 KVDC, and 50 mA. Shadow and plasma glow imaging techniques were used simultaneously for flow and plasma visualization. Shadow imaging, in the afore mentioned Mach numbers, shows that the plasma being discharged behind shock wave, in spite of increasing the magnetic field, has a slight effect on decreasing the intensity of the shock wave. With increasing Mach number, the Shock wave of the truncated conical nose moves downstream and as a result of the plasma discharge taking place below the nose and the constant magnetic field, the wave below the nose is eliminated. The experimental results indicate that at Mach number 2.45, the shock wave attaches to the truncated nose, thus; the continuous plasma discharge below the spike and in front of the wave eliminates the wave. This is the most important result of this study indicates that aero-spike plasma discharge can remove shock waves and thus reduce drag.

The study was a descriptive survey of solidarity which the purpose was the relationship between organizational trusts with organizational creation Bu-Ali Sina University, Hamadan. the population of this research consisted of all employees using stratified random sample of 260 numbers for example selected. To collect the data needed was used of questionnaire organizational trust and organizational creativity. To determination the validity Questionnaires for narrative approach used and for reliability is also using the Cronbach's alpha were calculated. For data analysis, in addition descriptive statistics from inferential statistics Pearson, Kolmogorov-Smirnov test, t-test for independent groups, and regression analysis. The results showed that there is a significant positive relationship between organizational trusts with organizational creation. The results of stepwise regression analysis showed that the trusted side has the greatest impact on organizational creativity.