Flutter parametric studies of cantilevered twin-engine transport type wing with and without winglet. Volume 2: Transonic and density effect investigations

Flutter characteristics of a cantilevered high aspect ratio wing with winglet were investigated. The configuration represented a current technology, twin engine airplane. Compressibility effects through transonic Mach numbers and a wide range of mass-density ratios were evaluated on a low speed and high speed model. Four flutter mechanisms were obtained from test, and analysis from various combinations of configuration parameters. It is shown that the coupling between wing tip vertical and chordwise motions have significant effect under some conditions. It is concluded that for the flutter model configurations studied, the winglet related flutter is amenable to the conventional flutter analysis techniques. The low speed model flutter and the high-speed model flutter results are described

Effects of winglet on transonic flutter characteristics of a cantilevered twin-engine-transport wing model

A transonic model and a low-speed model were flutter tested in the Langley Transonic Dynamics Tunnel at Mach numbers up to 0.90. Transonic flutter boundaries were measured for 10 different model configurations, which included variations in wing fuel, nacelle pylon stiffness, and wingtip configuration. The winglet effects were evaluated by testing the transonic model, having a specific wing fuel and nacelle pylon stiffness, with each of three wingtips, a nonimal tip, a winglet, and a nominal tip ballasted to simulate the winglet mass. The addition of the winglet substantially reduced the flutter speed of the wing at transonic Mach numbers. The winglet effect was configuration-dependent and was primarily due to winglet aerodynamics rather than mass. Flutter analyses using modified strip-theory aerodynamics (experimentally weighted) correlated reasonably well with test results. The four transonic flutter mechanisms predicted by analysis were obtained experimentally. The analysis satisfactorily predicted the mass-density-ratio effects on subsonic flutter obtained using the low-speed model. Additional analyses were made to determine the flutter sensitivity to several parameters at transonic speeds

Bhoi Khasi Compared to Standard Khasi

The paper briefly documents the Bhoi variety of Khasi, in comparison with the standard variety

Propagation of short period (10-40 min) atmospheric gravity waves from troposphere to mesosphere over Gadanki, India

The Indian MST radar at Gadanki (13.5°N, 79.2°E) has been utilised to conduct a detailed study of the close coupling between the troposphere and the mesosphere through the vertically propagating atmospheric gravity waves. For this purpose two cases from a special campaign dedicated to the simultaneous measurement of the fluctuations in the UTLS (Upper Troposphere and Lower Stratosphere) and in the mesosphere during 2001 and one case from a follow up observation in 2002 have been investigated. By using both the FFT and wavelet techniques, the near simultaneous tropospheric and mesospheric data of radar return signal strengths and tropospheric wind fields are analysed. The signatures of relatively high frequency gravity waves with periods between ~10 and 40 min have been clearly traced as propagating waves from the tropospheric turbulent layer heights (~8–18 km) to the lower mesospheric heights (65–80 km). Significant peak correlation coefficients of 0.56 and 0.45 have been found between the SNR time series of pairs of troposphere and mesosphere levels indicating the propagation of high speed gravity waves. The time series of wavelet spectra determined for the tropospheric SNR/zonal winds and the mesospheric SNR show that the detectability of the gravity waves increases at mesospheric heights. It is shown that the continuous SNR values received from the mesosphere can be used as an effective parameter for studies featuring mesospheric wave dynamics. Based on the observed values of vertical wavelengths and wave amplitudes, the horizontal wavelengths, wave phase and group velocities have been estimated for different wave periods. These results have implications on monitoring of the ubiquitous atmospheric gravity waves generated mainly by the tropospheric weather system of the tropical region from their imprint on the mesospheric turbulence structures

Ricci Solution in Kenmotsu Manifolds

In this paper we give a characterisation of Ricci solitons in Ricci recurrent and φ-recurrent Kenmotsu manifolds based on the 1-for

Indoor Rn-222 and Rn-220 variations: Evidence for Boyle's law

Background: Radon and its daughter product are a major source of natural radiation exposure, the measurement of radon concentration in dwellings is assuming ever increasing importance. It is known from recent surveys in many countries that radon and its progeny contributes significantly to total inhalation dose and is well established that radon when inhaled in large quantity causes lung disorder. In view of this the authors have measured Rn-222 and Rn-220 levels in dwellings of different volumes at Bangalore Metropolitan, India. Materials and Methods: Integrated and long duration measurements of radon were carried out using twin cup dosimeters with Solid State Nuclear Track Detector technique. Results: Results showed that concentrations of Rn-222, Rn-220, their progenies and dose rates in dwellings decreased with increase in room volume. Conclusions: The annual effective inhalation dose due to Rn-222, Rn-220 and their progenies from the study ranged between 0.2-4.4 with an arithmetic mean of 1.7 +/- 1.1 mSv y(-1). The dwellers of lower volumes are posed to high dose rates. Iran. J. Radiat. Res., 2012; 9(4): 231-23

Alignment and phylogenetic analysis of type II DNA topoisomerases

DNA topoisomerases have been evolved to solve the topological problems of DNA during replication, transcription, recombination and segregation. Discovery of several new enzymes and their characterization has necessitated this compilation. This analysis shows the distinct evolutionary relatedness of type II DNA topoisomerases. A striking feature is the absence of a contiguous stretch of about 160 amino acids in one of the subunits of prokaryotic type II enzymes, which might have important implications to their structure and function

Unusual occurrence of two species and rare occurrence of one sepceis of neritic squids off MangaIore coast

Cephalopods have a wide distribution in the seas around India, although only a few of them form a fishery at some centres. At Mangalore, cephalopods comprising mainly of Loligo duvaucelii (90%), Sepia aculeata and S. pharaonis constitute about 5-10%(962 tonnes in 1988) of the total trawl catch