RICEPEST, a model simulating yield losses due to several rice pests (sheath blight, brown spot, sheath rot, bacterial leaf blight, stem borers, brown plant hopper, defoliating insects, and weeds) ...under a range of specific production situations of tropical Asia was developed. The model was assessed, using: (1) combined data sets generated by a series of test-experiments conducted in different sites of the Philippines, India, and China; and (2) one additional, independent, validation-experiment where a wide range of production situations and injury profiles were manipulated at a single site. Model evaluation was based on the analysis of two output variables: grain yield and relative yield loss. The paper reports results of qualitative and quantitative methods used to assess RICEPEST. Qualitative evaluation involved visual examination of graphs where deviations (simulated minus observed) are plotted against simulated values, and displaying an area of acceptance. This method showed that, in general, RICEPEST accounted well for the yield reducing effects of rice pests. Two areas for potential improvement of RICEPEST were however, identified: the simulation of damage caused by dead hearts in water-stressed environments, and the simulation of damage caused by weeds. Quantitative evaluations made use of equivalence- and
χ
2-tests. The equivalence tests rejected (
P≤0.05) the hypothesis of difference between simulated and observed yield and relative yield loss larger than a preset tolerance in both test- and validation-experiments. Conversely, the
χ
2-tests did not reject the hypothesis of difference in categorised simulated and observed yields and relative yield losses (
P≤0.05) in both test- and validation-experiments. RICEPEST proved to simulate adequately yield losses and can be used as a tool to set research priorities for rice crop protection in tropical Asia.
The search for replacement of commutator and brushes in conventional DC motors by electronic commutator has resulted in a class of Permanent Magnet Brush Less (PMBL) motors. The operation of PMBL ...motor requires synchronization of coil currents with the instantaneous rotor position. The applied voltages of higher magnitudes must have same zero crossings as that of speed induced back EMF of the respective stator windings. The complexity of rotor position detection in PMBL motor is overcome by obtaining a replica of stator induced EMF using additional auxiliary stator and rotor. The auxiliary stator winding induced EMF is amplified using Power Operational Amplifier (P-OPAMP) and the output is connected to the main stator winding. The proposed scheme has been tested at laboratory scale and has been found to be a promising alternative scheme for operation of PMBLDC/AC motors.
Antioxidant activity (%) of Capparis spinosa leaves collected from nine different sites from three valleys in trans-Himalayan region of Ladakh (India) were measured using DPPH, ABTS and FRAP assay ...along with its polyphenol content. Maximum DPPH and ABTS radical scavenging activity was observed from leaves samples collected from Skuru and least from Tirchey site. FRAP assay revealed that Skuru site possess maximum antioxidant content as compared to the samples collected from any other location. IC50 of ABTS were quite reasonably correlated with FRAP assay (R2=0.517) while, DPPH IC50 was poorly correlated with both ABTS (R2=0.100) and FRAP assay (R2=0.223). The highest and lowest phenolic and flavonoid content was recorded in Skuru and Tirchey sites respectively. Total phenolics (27.62-21.42 mg GAE/g DW) and flavonoid content (6.96-2.69 mg quercetin equivalent/g DW) were found reasonably correlated with IC50 of ABTS (R2=0.741 and 0.703, respectively) and FRAP (R2=0.605 and 0.649, respectively) but poorly correlated with DPPH IC50 (R2=0.303 and 0.408, respectively). Results of present study confirmed the antioxidant potential of C. spinosa leaves collected from different locations of trans-Himalayas, whose phyto-chemistry and phyto-pharmacology should be investigated further in order to detect possible phyto-therapeutic uses where free radicals are implicated.
We have used reliable electron excitation cross sections in a simple Collisional-Radiative Model (CRM) to obtain the population densities of various excited levels for low electron temperature Ar ...discharges. Cross sections are obtained by using relativistic distorted wave theory for transitions from ground as well as excited states to the different higher lying levels of the Ar atom. We have compared our calculated population density results for 3p54s levels with recent exp erimental OES measurements.
The synthesis and characterization of degradable polymeric networks for biomedical applications was performed. Cross-linked films of poly(ε-caprolactone) (PCL) and poly(1,5-dioxepan-2-one) (PDXO) ...having various mole fractions of monomers and different cross-link densities were successfully prepared using 2,2′-bis-(ε-caprolactone-4-yl) propane (BCP) as cross-linking agent. Reaction parameters were carefully examined to optimise the film-forming conditions. Networks obtained were elastomeric materials, easy to cast and remove from the mould. Effect of CL content and cross-link density on the final properties of the polymer network was evaluated. High CL content or degree of cross-linking led to increase in Young's modulus and decrease in elongation at break. An increase in crystalline domains in films having a higher CL content was observed by optical microscopy. A greater thermal stability was observed in films having a high CL content. The hydrophilicity of the materials could be tailored by changing the CL content. The surface of the films became rougher with higher CL content.
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