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Showing 2 results for Naeimian
M. Farshbaf, M.a. Mofid, M. Belbasi, M. Jafarzadegan, H. Naeimian,
Volume 20, Issue 10 (October 2020)
Abstract
Thermal spraying is economical and rapid coating process that creates a rough and clean surface. As a result it can be used for applying the interlayer in transient liquid phase bonding. In the present study, transient liquid phase bonding Al 2024 to Ti-6Al-4V was investigated using brass interlayer, where the interlayer was Cu-Zn foil Cu-Zn thermal spray coat on Al substrate, respectively. The results show that by using thermal spray coat as interlayer, because of the formation of different defects that can be considered as diffusion channels, diffusion potential of Ti and Al becomes higher at the interface. It is concluded that the mechanism of bonding formation involves the diffusion of Cu into Al and Ti base materials and formation of TiAl، TiAl، Cu2 Al and AlCuMg phases and also diffusion of Cu through Al grain boundaries and formation of eutectic phases across the grain boundaries. The formation of these intermetallic phases was confirmed by energy dispersive spectroscopy and X-ray diffraction. Dissolution of the base metals in the joint area and the isothermal solidification process of the thermal sprayed interlayer is more and faster than the foil interlayer. The joint with thermal spray brass coat as interlayer, gives higher shear strength of 25 MPa in comparison with the case of using brass foil as interlayer (14.6 MPa). The decrease in bond strength can be attributed to aggregation and growth of the brittle intermetallics near the joint interface due to lower diffusion potential of Ti and Al in the joint zone.
Volume 21, Issue 2 (3-2019)
Abstract
Research on Organizational Citizenship Behaviour (OCB) has received a great deal of attention from researchers with the belief that empowerment in the organizations play a key role in the overall efficiency of the experts. The aim of this study was to determine relationship between organizational citizenship behaviour and empowerment. The methodological approach of this study was descriptive- correlative. The research population consisted of 177 extension experts, which was selected using randomized sampling method (n= 117). Validity of the instrument was established by a panel of experts consisting of senior faculty members and research committee advisors. Reliability analysis was conducted by using and Cronbach Alpha formula and result was 0.88. Necessary data was collected through Podsakoff questionnaire for organizational citizenship behavior. Empowerment questionnaire was self-made. The independent variables were dimensions of organizational citizenship behaviour (altruism, courtesy, sportsmanship, conscientiousness, and civic virtue). Dependent variable was empowerment. The results showed that 0.9, 66.6, and 32.5% of experts had, respectively, low, moderate, and high empowerment. Also, altruism, courtesy, conscientiousness, and civic virtue had positive significant relationship with empowerment. The results of the multiple regression analysis (stepwise method) revealed that courtesy and conscientiousness explained 41.2% of the variations in the experts’ empowerment.