Semi-empirical model for prediction of unsteady forces on an airfoil with application to flutter

A semi-empirical model is described for predicting unsteady aerodynamic forces on arbitrary airfoils under mildly stalled and unstalled conditions. Aerodynamic forces are modeled using second order ordinary differential equations for lift and moment with airfoil motion as the input. This model is simultaneously integrated with structural dynamics equations to determine flutter characteristics for a two degrees-of-freedom system. Results for a number of cases are presented to demonstrate the suitability of this model to predict flutter. Comparison is made to the flutter characteristics determined by a Navier-Stokes solver and also the classical incompressible potential flow theory

Inheritance of fruit colour in the Solanum nigrum complex

In the Solatium nigrum complex there is wide variability in the fruit colour. In 17 accessions representing diploids, tetraploids and hexaploids, dark shining blue, dull blue, bright red, orange red, yellowish-red and translucent green were observed in the different accessions. Blue is inherited as dominant over red and translucent green; however, the results obtained in crosses between blue and translucent green cannot be explained on the basis of this simple relationship and it is tentatively assumed that duplicate*genes are involved in this case. In the tetraploids S. nigrum, S. villosum and S. miniatum the different shades of red seem to be controlled by alleles at the same locus

A NOVEL VALIDATED HEADSPACE GAS CHROMATOGRAPHY METHOD FOR THE SIMULTANEOUS QUANTIFICATION OF THREE ORGANIC VOLATILE IMPURITIES IN ENROFLOXACIN PURE AND PHARMACEUTICAL DOSAGE FORMS

Objective: This article describes a novel, simple, and rapid gas chromatographic method for quantification of three organic volatile impurities (OVIs) present in enrofloxacin and its pharmaceutical dosage forms. Methods: As stationary phase using ZB-624 30 m×0.53 mm, 3.0 μ column with flame ionized detector at 250°C. The injector temperature is maintained at 180°C. The nitrogen gas was used as a carrier gas with a flow rate of 4.0 mL/min. The method involved a thermal gradient elution. The total run time is 21.14 min. Results: The retention time of three OVIs taken individually and in spiked standard solutions were determined. The retention times are 2.30 min for methanol, 7.07 min for 1-butanol, and 8.48 min for toluene, respectively. The % relative standard deviation for six injections should be not more than 10%. The % recovery ranges from 85 to 115%. The correlation coefficient (r2) for linearity is not <0.99. The limit of quantification was found to be 260 ppm for methanol, 101 ppm for 1-butanol, and 56 ppm for toluene. Furthermore, verified precision, ruggedness, robustness, solution stability, and pharmaceutical analysis. Conclusion: All the obtained results are found within the acceptable limits. The proposed method has been successfully applied for the quantification of OVIs present in enrofloxacin pure and its pharmaceutical dosage forms

Planetary Nebulae with Ultra-Violet Imaging Telescope (UVIT): Far Ultra-violet halo around the Bow Tie nebula (NGC 40)

Context. NGC 40 is a planetary nebula with diffuse X-ray emission, suggesting an interaction of the high speed wind from WC8 central star (CS) with the nebula. It shows strong Civ 1550 {\AA} emission that cannot be explained by thermal processes alone. We present here the first map of this nebula in C IV emission, using broad band filters on the UVIT. Aims. To map the hot C IV emitting gas and its correspondence with soft X-ray (0.3-8 keV) emitting regions, in order to study the shock interaction with the nebula and the ISM. This also illustrates the potential of UVIT for nebular studies. Methods. Morphological study of images of the nebula obtained at an angular resolution of about 1.3" in four UVIT filter bands that include C IV 1550 {\AA} and C II] 2326 {\AA} lines and UV continuum. Comparisons with X-ray, optical, and IR images from literature. Results. The C II] 2326 {\AA} images show the core of the nebula with two lobes on either side of CS similar to [N II]. The C IV emission in the core shows similar morphology and extant as that of diffuse X-ray emission concentrated in nebular condensations. A surprising UVIT discovery is the presence of a large faint FUV halo in FUV Filter with {\lambda}eff of 1608 {\AA}. The UV halo is not present in any other UV filter. FUV halo is most likely due to UV fluorescence emission from the Lyman bands of H2 molecules. Unlike the optical and IR halo, FUV halo trails predominantly towards south-east side of the nebular core, opposite to the CS's proper motion direction. Conclusions. Morphological similarity of C IV 1550 {\AA} and X-ray emission in the core suggests that it results mostly from interaction of strong CS wind with the nebula. The FUV halo in NGC 40 highlights the existence of H2 molecules extensively in the regions even beyond the optical and IR halos.Comment: 4 pages, 5 figures, accepted for publication as a letter in Astronomy & Astrophysic

Planetary Nebulae with UVIT II: Revelations from FUV vision of Butterfly Nebula NGC 6302

The high excitation planetary nebula, NGC 6302, has been imaged in two far-ultraviolet (FUV) filters, F169M (Sapphire; {\lambda}$_{\rm eff}$: 1608 {\AA}) and F172M (Silica; {\lambda}$_{\rm eff}$: 1717 {\AA}) and two NUV filters, N219M (B15; {\lambda}$_{\rm eff}$: 2196 {\AA}) and N279N (N2; {\lambda}$_{\rm eff}$: 2792 {\AA}) with the Ultra Violet Imaging Telescope (UVIT). The FUV F169M image shows faint emission lobes that extend to about 5 arcmin on either side of the central source. Faint orthogonal collimated jet-like structures are present on either side of the FUV lobes through the central source. These structures are not present in the two NUV filters nor in the FUV F172M filter. Optical and IR images of NGC 6302 show bright emission bipolar lobes in the east-west direction with a massive torus of molecular gas and dust seen as a dark lane in the north-south direction. The FUV lobes are much more extended and oriented at a position angle of 113{\deg}. They and the jet-like structures might be remnants of an earlier evolutionary phase, prior to the dramatic explosive event that triggered the Hubble type bipolar flows approximately 2200 years ago. The source of the FUV lobe and jet emission is not known, but is likely due to fluorescent emission from H$_2$ molecules. The cause of the difference in orientation of optical and FUV lobes is not clear and, we speculate, could be related to two binary interactions.Comment: 9 pages, 5 figures, accepted for publication in Astronomy & Astrophysic