the purpose of this study is estimate waiting time of frost occurrence over iran. the daily data from 663 synoptic and climatology over iran during 1/1/1340 to 11/10/1383 have been used. data interpolated by kriging method on 15ã—15 km pixels. the data base with dimension 15992ã—7187 obtained that on the rows were days and on the column were pixels. by t student test the interval mean of waitin...

Stem tissues of red-osier dogwood (Cornus stolonifera Michx.) acclimated from -3 C to -40 or -50 C in 8 to 10 weeks under a short photoperiod (9 hours) and controlled temperature conditions. During the summer months plants did not acclimate as well as at other times. The sequence of day/night temperature regimes which induced maximum acclimation was 20/15 C for 5 to 6 weeks; 15/5 C for 2 to 3 w...

In air-cooling applications with frost production, heat exchanger performance is often air-side limited, because the two-phase flow of the refrigerant provides excellent heat transfer coefficients, and because designers typically use a large air-side fin spacing for frost tolerance. The large fin spacing prolongs operation of the heat exchanger by mitigating the effect of the accumulating frost...