2,859 research outputs found

    An overlapped grid method for multigrid, finite volume/difference flow solvers: MaGGiE

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    The objective is to develop a domain decomposition method via overlapping/embedding the component grids, which is to be used by upwind, multi-grid, finite volume solution algorithms. A computer code, given the name MaGGiE (Multi-Geometry Grid Embedder) is developed to meet this objective. MaGGiE takes independently generated component grids as input, and automatically constructs the composite mesh and interpolation data, which can be used by the finite volume solution methods with or without multigrid convergence acceleration. Six demonstrative examples showing various aspects of the overlap technique are presented and discussed. These cases are used for developing the procedure for overlapping grids of different topologies, and to evaluate the grid connection and interpolation data for finite volume calculations on a composite mesh. Time fluxes are transferred between mesh interfaces using a trilinear interpolation procedure. Conservation losses are minimal at the interfaces using this method. The multi-grid solution algorithm, using the coaser grid connections, improves the convergence time history as compared to the solution on composite mesh without multi-gridding

    Alien Registration- Lessard, Thomas R. (Winslow, Kennebec County)

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    https://digitalmaine.com/alien_docs/16485/thumbnail.jp

    An apertureless near-field microscope for fluorescence imaging

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    We describe an apertureless near field microscope for imaging fluorescent samples. Optical contrast is generated by exploiting fluorescent quenching near a metallized atomic force microscope tip. This microscope has been used to image fluorescent latex beads with subdiffraction limit resolution. The use of fluorescence allows us to prove that the contrast mechanism is indeed spectroscopic in origin

    Study of gaseous exchanges in ensilage

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    Analysis of a high speed civil transport configuration at subsonic flow conditions using a Navier-Stokes solver

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    Computations of three dimensional vortical flows over a generic High Speed Civil Transport (HSCT) configuration with an aspect ratio of 3.04 are performed using a thin-layer Navier-Stokes solver. The HSCT cruise configuration is modeled without leading or trailing edge flap deflections and without engine nacelles. The flow conditions, which correspond to tests done in the NASA Langley 8-Foot Transonic Pressure Tunnel (TPT), are a subsonic Mach number of 0.3 and Reynolds number of 4.4 million for a range-of-attack (-.23 deg to 17.78 deg). The effects of the farfield boundary location with respect to the body are investigated. The boundary layer is assumed turbulent and simulated using an algebraic turbulence model. The key features of the vortices and their interactions are captured. Grid distribution in the vortex regions is critical for predicting the correct induced lift. Computed forces and surface pressures compare reasonably well with the experimental TPT data

    М. Ф. ФОН ДІТМАР – ЯСКРАВИЙПРЕДСТАВНИК ГІРНИЧОПРОМИСЛОВОЇ БУРЖУАЗІЇ ПІВДНЯ УКРАЇНИ(ОСТАННЯ ЧВЕРТЬ ХІХ– ПОЧАТОК ХХ СТ.)

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    В статті розглянуто постать відомого підприємця, науковця і суспільного діячаМ. Ф. фон Дітмара, визначено основні напрями його діяльності наПівдні Українив останній чверті ХІХ – на початку ХХ ст.The article considers the person of famous businessman, scientist and social activistM. F. von Ditmar, determines themain directions of his activity in SouthernUkraine in the last quarter ofXIX – the beginning ofXXcenturies

    Effecs of damage by wheat bug, Aelia germari [Hemiptera : Pentatomidae], on grain quality and on reproductive performance of the rice weevil, Sitophilus oryzae [Coleoptera : curculionidae]

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    La punaise des céréales, Aelia germari, cause des dégâts au champ, avant la maturité du grain, qui ont pour conséquence majeure une réduction de la valeur boulangère du blé destiné à la panification. Pour tenter de mettre en évidence les modifications induites par les attaques de punaises sur la valeur nutritive du grain, un essai biologique a été réalisé sur le charançon du riz Sitophilus oryzae, qui se développe dans l'endosperme du grain. Le charançon du riz a été élevé sur des échantillons de blé du cultivar 'Manondemias', dans lesquels ont été incorporés des taux différents (0, 4, 8, et 13%) de grain attaqué par la punaise phytophage A. germari. Sur les échantillons de blé punaisé à 4, 8 ou 13%, la durée moyenne de développement de S. oryzae était plus courte que sur le grain non punaisé. Cependant, le calcul des corrélations sur les variables prises deux à deux a montré que ni l'indice de sensibilité Dobie aux attaques d'insectes, ni la descendance par femelle de charançon, ni la perte de poids du grain consécutive au développement complet de S. oryzae, n'étaient corrélés avec le pourcentage de grains punaisés dans l'échantillon. À partir d'une analyse multivariable globale, associant les propriétés physicochimiques ou rhéologiques des grains avec les paramètres décrivant la réponse biologique du charançon S. oryzae, il a été montré que le blé sans attaque apparente de punaise pouvait être associé à une longue durée de développement pour S. oryzae, un nombre plus faible de descendants, une force boulangère, une teneur en azote et un temps de chute élevés, ainsi qu'à une faible teneur en cendres et en azote assimilable du grain.The wheat bug, Aelia germari, feeds on developing wheat kernels, causing a loss in baking quality of the harvested wheat (Triticum aestivum). The possible nutritional changes in the bug-damaged kernels after the harvest were tested in a bioassay using the rice weevil Sitophilus oryzae, which feeds on the kernel endosperm. The weevils were reared on baking wheat cultivar 'Manon demias', grown in Algeria, with different levels (0, 4, 8 and 13%) of wheat bug (A. germari) damaged kernels. Rice weevil reared on 4, 8 or 13% damaged wheat had a shorter development time than on wheat with no damage. However, pair-wise correlations showed that Dobie's index for susceptibility of grain for stored-products insect attack, number of progeny per female and kernel weight loss were not correlated with the percentage of damaged kernels. Using multivariate analysis, the general characteristics of high quality grain were associated with long development times for S. oryzae, low number of progeny, high baking strength, high falling number, high nitrogen, low ash content, and low assimilable nitrogen

    Rigorous numerics in floquet theory: Computing stable and unstable bundles of periodic orbits

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    In this paper, a rigorous method to compute Floquet normal forms of fundamental matrix solutions of nonautonomous linear differential equations with periodic coefficients is introduced. The Floquet normal form of a fundamental matrix solution F(t) is a canonical decomposition of the form F(t) = Q(t)eRt, where Q(t) is a real periodic matrix and R is a constant matrix. To rigorously compute the Floquet normal form, the idea is to use the regularity of Q(t) and to simultaneously solve for R and Q(t) with the contraction mapping theorem in a Banach space of rapidly decaying coefficients. The explicit knowledge of R and Q can then be used to construct, in a rigorous computer-assisted way, stable and unstable bundles of periodic orbits of vector fields. The new proposed method does not require rigorous numerical integration of the ODE

    Challenges in New Physics searches in top-like events at the LHC

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    The prospects of exploring physics beyond the standard model involving top quarks and top-like signals at the LHC based on Monte Carlo simulations at √s = 14 and 10TeV are reviewed. A special attention is given to results that can be expected for the early LHC running in 2010-2011. Consequently, the first section deals with the implications of having a center-of-mass energy lower than what was simulated, √s = 7TeV, for the first years of the LHC running. This will be done qualitatively by discussing the impact on the cross section of various production processes. Following this discussion, several searches for physics Beyond the standard model that are related to the top quark are described: top-antitop resonances, 4th generation of quarks, top charge, W polarization, anomalous Wtb vertex coupling, top-antitop spin correlation, and flavor changing neutral current. Their order of appearance goes from lower to higher integrated luminosity needed to obtain meaningful results out of each analysis
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