000687   Akpinar E K;Bicer Y (Mechanical Engineering Dep, Firat Univ, 23279, Elazig, Turkey, Email: ebruakpinar@firat.edu.tr) : Modelling of thin layer drying kinetics of sour cherry in a solar dryer and under open sun. J scient ind Res 2007, 66(9), 764-71.

Drying kinetics of sour cheery is investigated in solar dryer with forced convection and under open Sun with natural convection. Drying data were fitted to different mathematical models, whose performance was investigated by comparing coefficient (R). reduced chi-square (C²₅) and root mean square error (RMSE) between the observed and predicted moisture ratios. Among these models, drying model developed by Midilli and Kucuk model showed good agreement with the data obtained from the experiments in the solar dryer with forced convection drying mode. Logarithmic model has shown a better fit to the experimental sour cherries data for open sun drying with natural convection mode than the other models.

7 illus, 3 tables, 22 ref

000686   Agrawal A K;Raina S;Rajkumar;Kamath S (Microwave Tube Research & Development Centre, DRDO, , Bangalore-560 013, Email: agrawal_ak2000@yahoo.com) : Simulation of resonant meander-line attenuators for high-power helix traveling-wave tubes. Asian J Phys 2008, 17(2), 279-84.

A lossy meander-line, coated on dielectric helix-support rods, that provides resonant attenuation for high power traveling-live tubes was simulated by 3D modeling in HFSS (high frequency structure simulator) and the results validated against experiment with respect to the resonant frequency. The electric fields that are concentrated near the meander-line placed between the helix turns provided an effective attenuation at the resonant frequency. The helix dimensions and the meander-line dimensions significantly controlled the attenuation and the resonant frequencies, respectively.

5 illus, 1 table, 6 ref