a series of subsonic wind tunnel tests was conducted on an ogive-cylinder-flare configuration at zero angle of attack to study the effects of small helical protuberances on viscous drag reduction behavior. the experiments have been carried out on a smooth model and two wire-wrapped models with different spacing between the helical riblet rings, known as pitch length. in the present experiments,...

nitrogen foliar spray is one of the most important components in fertilizing programs for citrus in iran, as it can reduce nitrate leaching. the goal of this research was to determine the most effective concentration of foliar urea application on “thamson navel’’ orange trees, for achieving the highest yield. foliar sprays were carried out, in two stages with total concentrations of 0.4, 0.8 an...

Sex ratio, size at maturity, maturity stages, fecundity and egg diameter of Oreochromis niloticus from Coatetelco Lake, Morelos State, Mexico, were studied from January to December 1993. Sex ratio (male:female) was approximately 1:1.02. Length at maturity was 117 mm (males) and 120 mm (females). The fecundity ranged between 104 and 709 eggs, with egg diameter from 1,000 to 3,000 microns. The go...

effects of different paclobutrazol concentrations (0, 250, 350 and 450 mgl-1) and plantlet density (80, 100 and 120 plantlet/m2) on minituber production per plantlet in potato cultivar ‘sante’ were investigated in a factorial experiment based upon a randomized complete block design of 4 replications. paclobutrazol (cultar with 250 g/l of active ingredient) was used as foliar application at earl...

a brass vortex tube (vt) with interchangeable parts is used to determine the optimum cold end orifice diameter, main tube length and diameter. experiments were carried out to study the effects of operating pressure as well. it is shown that there is an optimum value for cold end orifice diameter, which is equal to 4mm and there is an optimum value for cold and hot exit temperature difference at...