The dynamics and control of large flexible space structures-IV

The effects of solar radiation pressure as the main environmental disturbance torque were incorporated into the model of the rigid orbiting shallow shell and computer simulation results indicate that within the linear range the rigid modal amplitudes are excited in proportion to the area to mass ratio. The effect of higher order terms in the gravity-gradient torque expressions previously neglected was evaluated and found to be negligible for the size structures under consideration. A graph theory approach was employed for calculating the eigenvalues of a large flexible system by reducing the system (stiffness) matrix to lower ordered submatrices. The related reachability matrix and term rank concepts are used to verify controllability and can be more effective than the alternate numerical rank tests. Control laws were developed for the shape and orientation control of the orbiting flexible shallow shell and numerical results presented

Interference mitigation in wireless mesh networks through radio co-location aware conflict graphs

Wireless Mesh Networks (WMNs) have evolved into a wireless communication technology of immense interest. But technological advancements in WMNs have inadvertently spawned a plethora of network performance bottlenecks, caused primarily by the rise in prevalent interference. Conflict Graphs are indispensable tools used to theoretically represent and estimate the interference in wireless networks. We propose a generic algorithm to generate conflict graphs which is independent of the underlying interference model. Further, we propose the notion of radio co-location interference, which is caused and experienced by spatially co-located radios in multi-radio multi-channel WMNs. We experimentally validate the concept, and propose a new all-encompassing algorithm to create a radio co-location aware conflict graph. Our novel conflict graph generation algorithm is demonstrated to be significantly superior and more efficient than the conventional approach, through theoretical interference estimates and comprehensive experiments. The results of an extensive set of ns-3 simulations run on the IEEE 802.11g platform strongly indicate that the radio co-location aware conflict graphs are a marked improvement over their conventional counterparts. We also question the use of total interference degree as a reliable metric to predict the performance of a Channel Assignment scheme in a given WMN deployment

Changes in the ducts of the glands of the hard palate in reverse smokers

Three hundred fifty-nine cases of stomatitis nicotina were studied in reverse smokers of home made chuttas. One hundred thirty-five biopsies of papular unbilicated lesions of stomatitis nicotina were studied histopathologically. The biopsies were chosen after toluidine blue staining. Mild dysplastic to severe dysplastic changes were seen around the openings of the ducts of the glands. There were three cases of microinvasive carcinoma in the one hundred thirty-five biopsies. Cystic dilatation of the ducts, due to obstruction of the ducts by keratotic plugging, was not seen in stomatitis nicotina lesions but was seen in elderly women who had smoked reverse for more than 4 to 5 decades. The ducts of the glands could probably form a portal of entry for the tobacco pyrolytic products which may act as carcinogenics

Histopathological Study of Stomatitis Nicotina

One hundred and thirteen biopsies of the palate in people accustomed to smoking cigars, most of them with the burning end of the cigar inside the mouth, have been studied

Language Identification: Contrivance Learning Process Using Web Based Disquisition

Language identification is the foremost task in the study of linguistics .The projections of language identification & conversions such as Google translate or any other hypothetical translator works in wonders. The mechanism of detecting the language performed by these translators is a real marvel. Hence in this divertissement it is of the primary importance to study the methods of identifying the language. In this paper, the methodologies of recognizing some of the Natural Languages such as English, Kannada, Hindi & Telugu is explained on the basis of N-Gram algorithm and the respective vowels and consonants of each of the languages are retrieved and stored for building the syntactic structure of the corpus

The dynamics and control of large flexible space structures-V

A general survey of the progress made in the areas of mathematical modelling of the system dynamics, structural analysis, development of control algorithms, and simulation of environmental disturbances is presented. The use of graph theory techniques is employed to examine the effects of inherent damping associated with LSST systems on the number and locations of the required control actuators. A mathematical model of the forces and moments induced on a flexible orbiting beam due to solar radiation pressure is developed and typical steady state open loop responses obtained for the case when rotations and vibrations are limited to occur within the orbit plane. A preliminary controls analysis based on a truncated (13 mode) finite element model of the 122m. Hoop/Column antenna indicates that a minimum of six appropriately placed actuators is required for controllability. An algorithm to evaluate the coefficients which describe coupling between the rigid rotational and flexible modes and also intramodal coupling was developed and numerical evaluation based on the finite element model of Hoop/Column system is currently in progress

Spin-lattice coupling mediated giant magnetodielectricity across the spin reorientation in Ca2FeCoO5

The structural, phonon, magnetic, dielectric, and magneto dielectric responses of the pure bulk Brownmillerite compound Ca2FeCoO5 are reported. This compound showed giant magneto dielectric response (10%-24%) induced by strong spin-lattice coupling across its spin reorientation transition (150-250 K). The role of two Debye temperatures pertaining to differently coordinated sites in the dielectric relaxations is established. The positive giant magneto-dielectricity is shown to be a direct consequence of the modulations in the lattice degrees of freedom through applied external field across the spin reorientation transition. Our study illustrates novel control of magneto-dielectricity by tuning the spin reorientation transition in a material that possess strong spin lattice coupling.Comment: 7 pages, 12 figure