8,794 research outputs found

    Pressure algorithm for elliptic flow calculations with the PDF method

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    An algorithm to determine the mean pressure field for elliptic flow calculations with the probability density function (PDF) method is developed and applied. The PDF method is a most promising approach for the computation of turbulent reacting flows. Previous computations of elliptic flows with the method were in conjunction with conventional finite volume based calculations that provided the mean pressure field. The algorithm developed and described here permits the mean pressure field to be determined within the PDF calculations. The PDF method incorporating the pressure algorithm is applied to the flow past a backward-facing step. The results are in good agreement with data for the reattachment length, mean velocities, and turbulence quantities including triple correlations

    INFLUENCE OF GRAM-NEGATIVE STRAIN KLEBSIELLA OXYTOCA ON BIOCORROSION

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    Several studies of biofilms must accept that biofilms may develop in an enormous number of environments. This biofilm forms colonization on the solid surfaces by extracellular polysaccharides (EPSs) secreted by the microbial cells. The EPSs secreted by microbial cell stimulate corrosion in the engineered materials due to the presence of polyanionic neutral macromolecules. Many techniques have been described measuring and inhibiting microbiologically influenced corrosion; however, none has been accepted as an industry standard. This is because the risks posed to the marine biosphere due to the use of antifouling inhibitors. Recently, a large amount of literature has been edited on the influence of toxic biocides on non-targeted organisms in the marine environment are most likely. It has been shown that the modifications of antifouling inhibitors by the non-toxic drugs can reduce microbial adhesion and some disentangle effects toward the environment. Hence, in this paper, the inhibition effect of neomycin trisulfate on the Klebsiella oxytoca on mild steel corrosion has been investigated using weight loss measurement, electrochemical impedance spectroscopy, Fourier-transform infrared, and scanning electron microscopy (SEM). These studies have shown that neomycin trisulfate shows better inhibition toward the microbe. The agreement with the experimental data was also found to be satisfactory. Further, surface morphological examination through SEM confirms that the inhibitor inhibits the microbes by blocking the EP

    On the Estimation of Elastic Scattering Cross Sections of Gamma Rays from Different Elements

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    Entropy measures for complex networks: Toward an information theory of complex topologies

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    The quantification of the complexity of networks is, today, a fundamental problem in the physics of complex systems. A possible roadmap to solve the problem is via extending key concepts of information theory to networks. In this paper we propose how to define the Shannon entropy of a network ensemble and how it relates to the Gibbs and von Neumann entropies of network ensembles. The quantities we introduce here will play a crucial role for the formulation of null models of networks through maximum-entropy arguments and will contribute to inference problems emerging in the field of complex networks.Comment: (4 pages, 1 figure

    Physical Properties of Metallic Antiferromagnetic CaCo{1.86}As2 Single Crystals

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    We report studies of CaCo{1.86}As2 single crystals. The electronic structure is probed by angle-resolved photoemission spectroscopy (ARPES) measurements of CaCo{1.86}As2 and by full-potential linearized augmented-plane-wave calculations for the supercell Ca8Co15As16 (CaCo{1.88}As2). Our XRD crystal structure refinement is consistent with the previous combined refinement of x-ray and neutron powder diffraction data showing a collapsed-tetragonal ThCr2Si2-type structure with 7(1)% vacancies on the Co sites corresponding to the composition CaCo{1.86}As2 [D. G. Quirinale et al., Phys. Rev. B 88, 174420 (2013)]. The anisotropic magnetic susceptibility chi(T) data are consistent with the magnetic neutron diffraction data of Quirianale et al. that demonstrate the presence of A-type collinear antiferromagnetic order below the Neel temperature TN = 52(1) K with the easy axis being the tetragonal c axis. However, no clear evidence from the resistivity rho(T) and heat capacity Cp(T) data for a magnetic transition at TN is observed. A metallic ground state is demonstrated from band calculations and the rho(T), Cp(T) and ARPES data, and spin-polarized calculations indicate a competition between the A-type AFM and FM ground states. The Cp(T) data exhibit a large Sommerfield electronic coefficient reflecting a large density of states at the Fermi energy D(EF), consistent with the band structure calculations which also indicate a large D(EF) arising from Co 3d bands. At 1.8 K the M(H) data for H|| c exhibit a well-defined first-order spin-flop transition at an applied field of 3.5 T. The small ordered moment of 0.3 muB/Co obtained from the M(H) data at low T, the large exchange enhancement of chi and the lack of a self-consistent interpretation of the chi(T) and M(H,T) data in terms of a local moment Heisenberg model together indicate that the magnetism of CaCo{1.86}As2 is itinerant.Comment: 18 pages, 15 figures, 4 tables, 61 references; v2: extended the fits of experimental data by additional electronic structure calculations; published versio

    Seamless Handover of Video Streamingin 4G Wireless Network

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    This paper presents QoS aware seamless vertical handover system for video streaming over wireless network. When the user is moving, the signal strength varies which may resultin buffering of the video. Various modulation techniques are used for continuous streaming of video and to resolve this issue. OFDM technique is used for multi carrier transmission with modulation formats such as BPSK and 16QAM.The system modulator switches between the two modulation schemes depending upon the Signal to Noise Ratio (SNR).In order to achieve continuous streaming of video the video is compressed at the time of handover. Experimental results shows that the performance of the system is better

    Hypothalamic control of food intake in cats and monkeys

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    The role of the central nervous system in regulating food intake was probably suggested first by the discovery that either obesity or emaciation may occur in patients with nervous diseases. For a while these observations were not properly evaluated, because emphasis was laid upon the obesity as such, or the leanness, rather than upon the changed eating habits responsible for the clinical picture. Interest was focused on the hypothalamic region by the experimental studies of many workers (Hetherington, 1941; Hetherington & Ranson, 1940, 1942 a, b; Brobeck, Tepperman & Long, 1943; Kennedy, 1950; Ranson, Fisher & Ingram, 1938) who showed that bilateral lesions in the medial hypothalamus, especially lesions in or ventro-lateral to the ventromedial nucleus, resulted in obesity. The confusion introduced by the notion that pituitary disturbances caused obesity was also clarified by Hetherington (1943), who showed that the hypophysis is in no way directly concerned with the pathogenesis of obesity following injury to the base of brain. Brobeck et al. (1943) demonstrated that this hypothalamic obesity was due to increased food intake (hypothalamic hyperphagia) rather than to disturbances in the fat, carbohydrate or intermediary metabolism. From the time of its discovery this hyperphagia was assumed to be a release phenomenon brought about through the destruction of an inhibitory mechanism.The existence of another mechanism in the lateral hypothalamus of the rat, which controls the 'instinct' or the 'urge' to eat, was demonstrated by Anand & Brobeck (1951 a, b). They showed that bilateral destruction of a well localized area in the lateral hypothalamus, at the same rostro-caudal level as the ventro-medial nucleus, produces complete aphagia and death due to starvation, in spite of the availability of food. It was also observed that of the two mechanisms the lateral one exerts the more basic type of control over food intake and the medial one (inhibitory) produces its effects only when the lateral is intact. The lateral mechanism is designated a 'feeding centre', or even an 'appetite centre', while the medial one is called a 'satiety centre'. Joliffe named the two, together, the 'appestat'. The present study was undertaken to determine, whether similar mechanisms exist in the hypothalamic regions of higher mammals, cats and monkeys, and also whether they are modified by the more highly evolved higher nervous centres
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