4,128 research outputs found
Radial Pulsations of an Infinite Cylinder of Finite Conductivity and of Variable Density in the Presence of a Magnetic Field
Land Use / Land Cover Change Detection in a part of Ramganga River Basin, at Bareilly District, Uttar Pradesh, India
The paper deals with the status of the land use/land cover change taken place in a part of Ramganga River Basin, at Bareilly district, Uttar Pradesh, India, by using remote sensing satellite data. The present study area is confined to latitude 28°10′ to 28054ʹ North and longitude 78°58′ to 78o58ʹ East, covering an area of 4120 km2. The satellite images of 1979 and 2009 have been obtained from global land cover facility (GLCF) and examined by unsupervised classification method. The general classification level has been adopted. The identified classes include Settlements, Croplands, Vegetation/Plantations, Water Bodies, and Waste Land. The result shows increasing trend of crop land and built up area and decreasing trend of vegetation and Plantation land
Optical Behavior of PANI/Sno2 Nanocomposites
This article reports the synthesis of Polyaniline (PANI) in Emeraldine form by in situ chemical oxidation method by using Ammonium persulphate as an oxidizing agent and a simultaneous synthesis of polyaniline (PANI)/SnO2 nanocomposites. The UV-Vis absorption spectra were studied to explore the optical behavior after incorporating SnO2 nanoparticles into PANI matrix. The absorption bands for the PANI/SnO2 sample were observed at ~370nm, ~550 nm and ~910 nm wavelengths. This, however shows significant shifts in the absorption spectral to higher wavelength when comparing the absorption spectrum of both PANI and PANI/SnO2. These bands may well correspond to ?-?* transition, polaron-?* transition and polaron-? transition, respectively. This could be attributed to the successful interaction of the SnO2 with the polymer chain. Hence, such shifts in absorption peak positions are related to the presence of the SnO2 in the matrix of PANI. The Attenuated Total Reflectance (ATR) spectrum of PANI/SnO2 provided the characteristic absorption peaks at 3227.54cm-1,1569.03cm-1, 1496.71cm-1, 1444.86cm-1, 1289.13cm-1, 1145.65cm-1,821.57cm-1, 506.68cm-1, and 412.08cm-1 due to the provision of information about the changes in the chemical structure of polymer. ATR spectra also give indication that the incorporation of SnO2 in the matrix of PANI seems to be effective for the improvement of the physicochemical properties of conducting polymers
Battle of the sexes over paternity
Reproductive behaviors have evolved through severe inter-sexual competition. We have recently described a behavior in post-mated female Drosophila melanogaster that controls ejaculate retention and sperm storage, and is a possible mechanism by which females who have mated with several partners can choose which sperm that is stored and used for fertilization. This behavior can also regulate exposure of the female to harmful effects of male SFP that are present in the ejaculate. Our study identified the neural pathway functioning in the female brain that regulates this behavior
Universal Baxterization for -graded Hopf algebras
We present a method for Baxterizing solutions of the constant Yang-Baxter
equation associated with -graded Hopf algebras. To demonstrate the
approach, we provide examples for the Taft algebras and the quantum group
.Comment: 8 page
SPH Simulations of Direct Impact Accretion in the Ultracompact AM CVn Binaries
The ultracompact binary systems V407 Vul (RX J1914.4+2456) and HM Cnc (RX
J0806.3+1527) - a two-member subclass of the AM CVn stars - continue to pique
interest because they defy unambiguous classification. Three proposed models
remain viable at this time, but none of the three is significantly more
compelling than the remaining two, and all three can satisfy the observational
constraints if parameters in the models are tuned. One of the three proposed
models is the direct impact model of Marsh & Steeghs (2002), in which the
accretion stream impacts the surface of a rapidly-rotating primary white dwarf
directly but at a near-glancing angle. One requirement of this model is that
the accretion stream have a high enough density to advect its specific kinetic
energy below the photosphere for progressively more-thermalized emission
downstream, a constraint that requires an accretion spot size of roughly
1.2x10^5 km^2 or smaller. Having at hand a smoothed particle hydrodynamics code
optimized for cataclysmic variable accretion disk simulations, it was
relatively straightforward for us to adapt it to calculate the footprint of the
accretion stream at the nominal radius of the primary white dwarf, and thus to
test this constraint of the direct impact model. We find that the mass flux at
the impact spot can be approximated by a bivariate Gaussian with standard
deviation \sigma_{\phi} = 164 km in the orbital plane and \sigma_{\theta} = 23
km in the perpendicular direction. The area of the the 2\sigma ellipse into
which 86% of the mass flux occurs is roughly 47,400 km^2, or roughly half the
size estimated by Marsh & Steeghs (2002). We discuss the necessary parameters
of a simple model of the luminosity distribution in the post-impact emission
region.Comment: 24 pages, 5 figures, Accepted for publication in Ap
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