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The iterative Fast Fourier technique to array failure correction with placement of single wide nulls and dual wide nulls while keeping the side lobe level to its minimum value; are presented in this paper. The paper describes the iterative Fourier technique for the synthesis of low-side lobe patterns for linear arrays with uniform element spacing. The method uses the property that for a linear array with uniform element spacing, an inverse Fourier transform relationship exists between the array factor and the element excitations. This property is used in an iterative way to derive the array element excitations from the prescribed array factor. The effectiveness of this method for realizing lower values of side lobe levels and placing the single wide nulls and dual wide nulls at different FFT points will be demonstrated for linear arrays equipped with 34 elements. This demonstration of effectiveness also involves the recovery of the original low-side lobe levels as close as possible, in case of element failures.

Jatropha oil (Jatropha curcas L.), a non-edible oil with oleic acid (45.7%) and linoleic acid (33%) as major components, was used to prepare basestocks for biolubricants. The hydrolyzed fatty acids underwent reaction with two iso-alcohols, 2-ethyl-1-hexanol (EH) and 3,5,5-trimethyl-1-hexanol (TMH) and 5 different polyols, namely neopentyl glycol (NPG), 2-methyl-2-propyl-1,3-propandiol (MPPD), trimethylolpropane (TMP), trimethylolethane (TME) and pentaerythritol (PE) at around 140 ºC in presence of catalyst p-toluenesulfonic acid (p-TSA) and xylene as solvent. The yields for the branched mono- and polyol esters ranged from 90% to 97.5%. The physico-chemical, lubricant and tribological properties of these esters as well as their 1H NMR, 13C NMR, IR and ESI-MS techniques were investigated. Among the products, polyol esters were found to possess good viscosity indices, good foam stability, higher thermal stability and higher flash and auto ignition points compared to branched mono esters. TMP and TME esters have matched the specifications of ISO VG 46 and PE esters match ISO VG 68 fire resistant hydraulic fluids, which are in high demand.