Present study was carried out to evaluate the effect of various dehydration techniques such as sun drying, solar drying, dryingafter freezing (Freeze for one hour followed by mechanical drying at 55°C), vacuum drying and drying using lab scale air oven onproximate composition and retention of antioxidants in different fruit powder prepared from Bael (Aegle marmelos) and Palmyra(Borassus flabellifer). Moisture content, Total Ash, Crude fiber %, Fat %, Crude protein %, total phenolic content,β –Caroteneand antioxidant activity were tested. The antioxidant activity was measured based on the ability of fruit extract to scavenge 1, 1-diphenyl-2-picrylhydrazyl (DPPH). Among different drying treatments the highest fat percentage recorded by the solar driedpalmyra fruit powder and there is no significant difference (α= 0.05) between sun drying and vacuumed drying. Higherconcentration of β -Carotene and total phenolic content were recorded in vacuum dried samples both in bael and Palmyra fruitpowders and it significantly different (α= 0.05) from other treatments. The scavenging activity of bael fruit powder in vacuumdrying was ranged from 65.36% to 81.33% of the concentration 200 μg/ml to1000 μg/ml and the palmyra fruit powder wasrecorded 57.32% to 83.25% of the concentration 200 μg/ml to1000 μg/ml. Vacuum dried fruit powders of palmyra and bael weregiven highest radical scavenging activity and the scavenging activity of palmyra fruit powder is higher than the bael. Thereforevacuum drying can be recommended as the most effective drying method to protect chemical characteristics and retention ofantioxidant properties of fruit powders.
Modelling forest tree volumehas a long history due to its importance in forest management decision making. However, tree biomass prediction become more popular recently because it has a strong relationship with carbon sequestration. Over the years, numerous attempts were made to construct allometric models in predicting tree volume and biomass in Sri Lanka for different forest species. Volume and biomass estimation in forest trees in Sri Lanka can be divided into four main types, i.e., (i) use of specific models built for the target species, (ii) use of models originally built for different tree species from the target once, (iii) use of common/universal conversions and (iv) use of remote sensing related studies. The first three types, however, became more common because mainly remote sensing studies do not facilitate the biomass estimation at the tree level. Details of tree volume and biomass prediction models constructed for Eucalyptus grandis, E.torelliana, E. microcorys, Tectona grandis, Pinus caribaea, Khaya senegalensis and Alstonia macrophylla are discussed in this paper. Moreover, it discusses the result of a study conducted in a wet zone natural forest to predict species-specific individual tree biomass using diameter as the only explanatory variable. Finally it elaborates the issues faced in developing allometric equations in Sri Lanka.
Detection of corners is an important task in computer vision to capture discontinuous boundaries of objects of interest. Present operators designed to detect boundaries having sharp corners often produce unsatisfactory results because the points detected can also be an isolated point, ending of a thin line or a maximum curvature region of a planar curve. A novel corner detection operator, capable of detecting corner points that exist only on the boundary of an object, is presented in this paper. Initially, candidate corner points are detected by exploiting intensity information of the local neighborhood and associated connectivity pattern around the center point within a local window. Further verification is done to confirm whether the detected corner point is on the boundary of the targeted object. As the proposed operator is isotropic, it covers all the orientations and corner angles by performing a single computation step within the local window. The performance of the operator is tested with both synthetic and real images and the results are compared with other major corner detectors