7,586 research outputs found

    Mathematical Analysis of Single and Two Phase Flow of Blood in Narrow Arteries with Multiple Contrictions

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    The pulsatile flow of blood in narrow arteries with multiple-stenoses under body acceleration is analyzed mathematically, treating blood as (i) single-phase Herschel-Bulkley fluid model and (ii) two-phase Herschel-Bulkley fluid model. The expressions for various flow quantities obtained by Sankar and Ismail (2010) for single-phase Herschel-Bulkley fluid model and Sankar (2010c) for two-phase Herschel-Bulkley fluid model are used to compute the data for comparing these fluid models in a new flow geometry. It is noted that the plug core radius, wall shear stress and longitudinal impedance to flow are marginally lower for two-phase H-B fluid model than those of the single-phase H-B fluid model. It is found that the velocity decreases significantly with the increase yield stress of the fluid and the reverse behavior is noticed for longitudinal impedance to flow. It is also noticed that the velocity distribution and flow rate are higher for two-phase Herschel-Bulkley fluid model than those of the single-phase Herschel-Bulkley fluid model. It is also recorded that the estimates of the mean velocity increase with the increase of the body acceleration and this behavior is reversed when the stenosis depth increases

    Chemical characterization of atmospheric particulate matter in Delhi, India, part II: Source apportionment studies using PMF 3.0

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    World Bank reports Delhi as a second most polluted megacity in the world for particulates pollution. In Delhi, PM10 (d ≤ 10 μm) aerosol samples were monitored throughout 2008 and their characterization for major chemical elements (Na, Mg, Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Br, Sr, Ba, Pb, Cd, Sn and Sb) and ions (Cl-, NO3-, SO42-, Na+, NH4+, K+, Mg2+ and Ca2+) have been documented in an earlier study. To resolve complexity in source apportionment for chemical constituents in PM10, UNMIX 6.0 and Positive Matrix Factorization (PMF 3.0) models are applied. Four factors were derived to explain routine sources of PM10 (crustal origin, road-traffic and secondary aerosols). Factor-1, designated as road-traffic source, has been determined by temporal correlation among Pb, Cu, Zn, Ni and V with strong correlation between Pb and Zn. This source factor-1 has shown more than 60% contribution to receptor site. Factor-2, referred as crustal origin due to strong inter-relationship among Si, Fe, Al, Ca and Mg, has also shown to be significant contribution to similar species in receptor matrix. Factor-3 ( NH4+, NO3-) has been differentiated due to contribution of secondary aerosols in the receptor region. This factor-3 has indicated major fraction of these ionic species for their uniform percentage variability, where mean values have been projected close to 75th percentile. Surprisingly, source factor-4 has explained the specific chloride source in the region with major contribution of 86%. For policymakers, results presented would serve as benchmark of source apportionments in Delhi

    Charge Lattices and Consistency of 6D Supergravity

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    We extend the known consistency conditions on the low-energy theory of six-dimensional N = 1 supergravity. We review some facts about the theory of two-form gauge fields and conclude that the charge lattice Gamma for such a theory has to be self-dual. The Green-Schwarz anomaly cancellation conditions in the supergravity theory determine a sublattice of Gamma. The condition that this sublattice can be extended to a self-dual lattice Gamma leads to a strong constraint on theories that otherwise appear to be self-consistent.Comment: 15 pages. v2: minor changes; references, additional example added; v3: minor corrections and clarifications added, JHEP versio

    Asymmetry to symmetry transition of Fano line-shape: Analytical derivation

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    An analytical derivation of Fano line-shape asymmetry ratio has been presented here for a general case. It is shown that Fano line-shape becomes less asymmetric as \q is increased and finally becomes completely symmetric in the limiting condition of q equal to infinity. Asymmetry ratios of Fano line-shapes have been calculated and are found to be in good consonance with the reported expressions for asymmetry ratio as a function of Fano parameter. Application of this derivation is also mentioned for explanation of asymmetry to symmetry transition of Fano line-shape in quantum confined silicon nanostructures.Comment: 3 figures, Latex files, Theoretica

    対流圏に見られる鉛直微細構造

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    We report the design, synthesis, detailed characterization, and analysis of a new multifunctional pi-conjugated bola-amphiphilic chromophore: oligo-(p-phenyleneethynylene)-dicarboxylic acid with dialkoxyoctadecyl side chains (OPE-C-18-1). OPE-C-18-1 shows two polymorphs at 123 K (OPE-C-18-1') and 373 K (OPE-C-18-1 `'), whose crystal structures were characterized via single crystal X-ray diffraction. OPE-C-18-1 also exhibits thermotropic liquid crystalline property revealing a columnar phase. The inherent pi-conjugation of OPE-C-18-1 imparts luminescence to the system. Photoluminescence measurements on the mesophase also reveal similar luminescence as in the crystalline state. Additionally, OPE-C-18-1 shows mechano-hypsochromic luminescence behavior. Density functional theory (DFT)-based calculations unravel the origins behind the simultaneous existence of all these properties. Nanoindentation experiments on the single crystal reveal its mechanical strength and accurately correlate the molecular arrangement with the liquid crystalline and mechanochromic luminescence behavior

    Characterisation of atmospheric aerosol by SEM-EDX and Ion-chromatography techniques for eastern Indo-Gangetic plain location, Varanasi, India

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    Atmospheric aerosol consists of both natural and anthropogenic origin. Studies have shown that continuous exposure to these particles is associated with a high percentage of death from respiratory and cardiovascular disease. In the present study, we have first time used both SEM-EDX analysis as well as chemical analysis to understand the differences in morphology and elemental composition of aerosols sample from a suburban clean and green area of Banaras Hindu University campus and some much polluted urban areas of the Varanasi city situated in the eastern Indo-Gangetic plain. The analysis was done by using scanning electron microscope (SEM) coupled with energy dispersive X-ray microanalyzer (EDX) and ionchromatography (IC). Analyses show that C, Ca, Na, S, Si, Al have dominated the sample

    F-Theory and the Mordell-Weil Group of Elliptically-Fibered Calabi-Yau Threefolds

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    The Mordell-Weil group of an elliptically fibered Calabi-Yau threefold X contains information about the abelian sector of the six-dimensional theory obtained by compactifying F-theory on X. After examining features of the abelian anomaly coefficient matrix and U(1) charge quantization conditions of general F-theory vacua, we study Calabi-Yau threefolds with Mordell-Weil rank-one as a first step towards understanding the features of the Mordell-Weil group of threefolds in more detail. In particular, we generate an interesting class of F-theory models with U(1) gauge symmetry that have matter with both charges 1 and 2. The anomaly equations --- which relate the Neron-Tate height of a section to intersection numbers between the section and fibral rational curves of the manifold --- serve as an important tool in our analysis.Comment: 29 pages + appendices, 5 figures; v2: minor correction

    Anomaly Cancelation in Field Theory and F-theory on a Circle

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    We study the manifestation of local gauge anomalies of four- and six-dimensional field theories in the lower-dimensional Kaluza-Klein theory obtained after circle compactification. We identify a convenient set of transformations acting on the whole tower of massless and massive states and investigate their action on the low-energy effective theories in the Coulomb branch. The maps employ higher-dimensional large gauge transformations and precisely yield the anomaly cancelation conditions when acting on the one-loop induced Chern-Simons terms in the three- and five-dimensional effective theory. The arising symmetries are argued to play a key role in the study of the M-theory to F-theory limit on Calabi-Yau manifolds. For example, using the fact that all fully resolved F-theory geometries inducing multiple Abelian gauge groups or non-Abelian groups admit a certain set of symmetries, we are able to generally show the cancelation of pure Abelian or pure non-Abelian anomalies in these models.Comment: 48 pages, 2 figures; v2: typos corrected, comments on circle fluxes adde
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