Perlette is a popular cultivar of grapes (Vitis vinifera L.) in India. It do not have compatible and efficient rootsystem to be successful in Indian soils. The rootstocks viz. St. George, C-1616, C-1613 were never tested for this variety in India. The compatibility of Perlette with these rootstocks and efficiency of these rootstocks in terms of nitrogen, potassium, phosphorous and sulphur absorption and in checking the accumulation of sodium and chloride salts were tested. The incidence of Anthracnose, Cercospora leaf spot and Downy Mildew was also investigated. The effect of these rootstocks...

The concept of V-shaped rib was developed to capitalize on this span-wise variation of heat transfer for inclined ribs. The V-shaped rib reduced span-wise variation of heat transfer and increased average heat transfer. The heat transfer results have been compared with those for smooth ducts under similar flow and thermal boundary conditions. It is found that the angled ribs give higher heat transfer rate than transverse ribs, because of the secondary flow induced by the rib angle, in addition to breaking the laminar sub-layer and producing local wall turbulence. The results show that the...

The term solar air heating refers to a technology in which the radiant energy emitted by the sun is captured in an absorber and used for space heating. Needless to say, it is a renewable and pollution-free method to produce space heating, and when used in commercial buildings or industries, it could be very cost-effective. Conventional solar air heaters have low thermal efficiency because of the low heat transfer coefficient between the absorber plate and air, leading to a higher absorber temperature and hence higher thermal losses. Attempts have been made to increase heat transfer to air...

An investigation is done in relation to heat transfer enhancement in solar air heaters with circular V-shaped down ribs. Ribs were attached to the absorber plate, having an angle of attack ( = 60 ). The ratio of rib height to hydraulic diameter (e/D) was 0.047, while the range of rib pitch-to-height ratio was (P/e = 4, 8, and 16) mm for three different sheets, with the Reynolds number ranging from (Re = 1825-7759). The roughened wall of the duct is heated by direct sunlight, while the remaining three walls are insulated. The concept of a V-shaped rib was developed to capitalise on this...