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Browsing School of Science (SSC) by Subject "Alkali Metal"

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    The effect of grain growth of electrode material on power output of alkali metal thermal electric converter
    (University of Management and Technology Lahore, 2015) Anwar, Muhammad Talha
    The Alkali Metal Thermal Electric Converter (AMTEC) is one of the most desirable device for directly converting heat into electrical energy among the thermal convertors. Electrode and electrolyte, components of AMTEC play an impotent role in the degradation of power output. This research work is focused on the electrodes of the AMTEC. Power output can be controlled by improving electrodes of the AMTEC for the use of long time operation. The effect of time of operation of AMTEC when operated continuously for 150,000 hours is studied on the degradation power output. The power output declines as, the time of operation increases. This is because of the electrode material. The grain size of the electrodes material increases with time of operation. The grain size increment reduces the power output. We examine values of grain size by keeping time of operation the same but vary the parameter “a”, the grain size increases with the increases of “a”. The degradation of power output occurs 28 % after 150000-hour operation. It is observed R_f remains almost constant for all time operation for smaller values of a = 1.141 × 〖10〗^9 but for higher values of “a”, R_f start increasing rapidly. The parameter “a” has been usually treated as constant for all practical purposes. It is proportional to a product of M_0 and γ_s. The value of γ_s decreases as the temperature increases, whereas M_0 increases as the temperature increases. As the mobility parameter “a” remains constant to some extent. However, when the temperature goes very high the parameter “a” may not remain constant as the proportionality of “a” to M_0 and γ_s is not of the same order. At high temperatures one may out weight the other and thus “a” may not remain constant at advanced temperatures. This works through has been done at one temperature ≈ 1023 K but analyzed the effect of “a” on the grain size and thus on power output. Power degrades as the grain size increases. For smaller values of parameter “a” grain size remains almost constant for all time of operation. But for higher values of “a “grain size increases rapidly, no matter for how long the operation is supported. So the degradation of power depends upon the increase in grain size and for the larger values of parameter “a”.