3,582 research outputs found

    Computer program for the analysis of the cross flow in a radial inflow turbine scroll

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    A computer program was used to solve the governing of the potential flow in the cross sectional planes of a radial inflow turbine scroll. A list of the main program, the subroutines, and typical output example are included

    Analysis of the cross flow in a radial inflow turbine scroll

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    Equations of motion were derived, and a computational procedure is presented, for determining the nonviscous flow characteristics in the cross-sectional planes of a curved channel due to continuous mass discharge or mass addition. An analysis was applied to the radial inflow turbine scroll to study the effects of scroll geometry and the through flow velocity profile on the flow behavior. The computed flow velocity component in the scroll cross-sectional plane, together with the through flow velocity profile which can be determined in a separate analysis, provide a complete description of the three dimensional flow in the scroll

    Analysis of a diffusive effective mass model for nanowires

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    We propose in this paper to derive and analyze a self-consistent model describing the diffusive transport in a nanowire. From a physical point of view, it describes the electron transport in an ultra-scaled confined structure, taking in account the interactions of charged particles with phonons. The transport direction is assumed to be large compared to the wire section and is described by a drift-diffusion equation including effective quantities computed from a Bloch problem in the crystal lattice. The electrostatic potential solves a Poisson equation where the particle density couples on each energy band a two dimensional confinement density with the monodimensional transport density given by the Boltzmann statistics. On the one hand, we study the derivation of this Nanowire Drift-Diffusion Poisson model from a kinetic level description. On the other hand, we present an existence result for this model in a bounded domain

    Searching for Charged Higgs Bosons in the BLB-L Supersymmetric Standard Model at the High Luminosity Large Hadron Collider

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    Upon assuming the BLB-L Supersymmetric Standard Model (BLSSM) as theoretical framework accommodating a multi-Higgs sector, we assess the scope of the High Luminosity Large Hadron Collider (HL-LHC) in accessing charged Higgs bosons (H±H^\pm) produced in pairs from ZZ' decays. We show that, by pursuing both di-jet and tau-neutrino decays, several signals can be established for H±H^\pm masses ranging from about MWM_{W} to above mtm_t and ZZ' masses between 2.5 TeV and 3.5 TeV. The discovery can be attained, even in a background free environment in some cases, owing to the fact that the very massive resonating ZZ' ejects the charged Higgs bosons at very high transverse momentum, a kinematic region where any SM noise is hugely depleted.Comment: 5 pages, 7 figures, matches published versio

    An effective mass theorem for the bidimensional electron gas in a strong magnetic field

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    We study the limiting behavior of a singularly perturbed Schr\"odinger-Poisson system describing a 3-dimensional electron gas strongly confined in the vicinity of a plane (x,y)(x,y) and subject to a strong uniform magnetic field in the plane of the gas. The coupled effects of the confinement and of the magnetic field induce fast oscillations in time that need to be averaged out. We obtain at the limit a system of 2-dimensional Schr\"odinger equations in the plane (x,y)(x,y), coupled through an effective selfconsistent electrical potential. In the direction perpendicular to the magnetic field, the electron mass is modified by the field, as the result of an averaging of the cyclotron motion. The main tools of the analysis are the adaptation of the second order long-time averaging theory of ODEs to our PDEs context, and the use of a Sobolev scale adapted to the confinement operator

    Evaluation of certain Nitrogen-Fixing Bacteria against Fusarium spp. infected peanut

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    In this study, the inhibition of soil borne pathogenic fungi Fusarium spp. that cause root and pod rot diseases in peanut (Arachis hypogaea) was investigated by using  soil-isolated Plant Growth Promoting Rhizobacteria (PGPR), (Azotobacter and Azospirillum) and root-nodule Brady- Rhizobium as biological agents. Twenty seven isolates of  Azotobacter  and  26 isolates of  Azospirillum obtained from rhizosphere of peanut plants, The efficiency of the nitrogenase activity was estimated and the best four  Azotobacter isolates including (A3, A7, A11, and A20) and three Azospirillum isolates including (AZ2, AZ14 and AZ18) were selected as the most efficient in  nitrogenase activity. These isolates were subjected to test their ability in solubilizing zinc and phosphate and their strength in direct antagonism. The isolates A7 and Az18 were more efficient in solubilizing Phosphate and zinc. Azospirillum sp. AZ18, Azotobacter sp. A7 and Brady-Rhizobium sp. B-Rh1 achieved the highest reduction percentage in mycelia linear growth of pathogenic fungi in vitro. Under greenhouse conditions, Azotobacter sp. A7 recorded the highest disease reduction percentage of peanut root rot (44.38 %). Furthermore, Brady-Rhizobium sp. B-Rh1 recorded the highest disease reduction of peanut pod rot (50.6%) followed by Azotobacter sp. A7 (47.62%). In addition, our results showed that inoculation with the tested nitrogen fixing bacteria gave remarkable increase in the yield parameters of peanut plants such as number and weight of pods and  increased the vegetative biomass overall

    LQ Robust Synthesis With Non-fragile Controllers: The Static State Feedback Case

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    This paper describes the synthesis of Non-fragile or Resilient regulators for linear systems. The general framework for fragility is described using state space methodologies and the LQH static state feedback case is examined in detail. We discuss the multiplicative structured uncertainties case and propose remedies of the fragility problem. The benchmark problem is taken as example to show how an uncertain or resilient static state feedback controller can affect the performance of the system

    Caracterización del área de puesta de especies de túnidos en las costas del norte de Túnez

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    Early life stages of tuna species were investigated along the northern coasts of Tunisia in the summer of 2010, from 7 to 14 July. A total of 74 stations, distributed on a regular grid, were sampled. Larvae of five tuna species were identified: the Atlantic bluefin tuna, the bullet tuna, the Atlantic black skipjack, the Atlantic bonito and the albacore tuna. Larval distribution patterns show that Atlantic bluefin tuna and albacore tuna usually spawn in offshore oligotrophic waters and Atlantic black skipjack larvae on the continental shelf. The widespread distribution of bullet tuna larvae, suggests that it spawns on the entire continental shelf and over the shelf break. The results from the quotient analysis carried out to characterize the spawning habitat of each species, show that the input of recent surface Atlantic water (AW) masses play a key role in the spawning strategy of tuna species, particularly in the case of the Atlantic bluefin tuna, whose larvae were mainly caught in the mixed waters resulting from the interaction between recent AW and resident AW, as demonstrated by their preference for salinity values between 36.9 and 37.4.Se investigaron las fases larvarias tempranas de especies de túnidos a lo largo de las costas del norte de Túnez, durante el verano de 2010, del 7 al 14 de julio. Se muestrearon un total de 74 estaciones, distribuidas en una malla regular. Se identificaron larvas de cinco especies: el atún rojo, la melva, la bacoreta, el bonito y el atún blanco. Los patrones de distri-bución de larvas muestran que el atún rojo y el atún blanco desovan generalmente en aguas oligotróficas alejadas de la costa. Por contra, la localización relativamente más costera de las larvas de bacoreta indica que esta especie se reproduce sobre la plataforma continental, mientras que la amplia distribución de las larvas de melva sugiere que esta especie desova a lo largo de toda la plataforma y el margen continental. Los resultados del análisis de proporcionalidad, llevado a cabo para caracteri-zar el hábitat de puesta de cada especie, muestran que la entrada de masas de agua superficial atlántica (AW) reciente juegan un papel clave en la estrategia de desove de las especies de túnidos, sobre todo en el caso del atún rojo, cuyas larvas fueron capturadas principalmente en las aguas de mezcla, resultantes de la interacción entre el AW reciente y la residente, como lo demuestra su preferencia por los valores de salinidad entre 36.9 y 37.4.Versión del editor1,006

    Beyond Halo and Wedge: Visualizing out-of-view objects on head-mounted virtual and augmented reality devices

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    Head-mounted devices (HMDs) for Virtual and Augmented Reality (VR/AR) enable us to alter our visual perception of the world. However, current devices suffer from a limited field of view (FOV), which becomes problematic when users need to locate out of view objects (e.g., locating points-of-interest during sightseeing). To address this, we developed and evaluated in two studies HaloVR, WedgeVR, HaloAR and WedgeAR, which are inspired by usable 2D off-screen object visualization techniques (Halo, Wedge). While our techniques resulted in overall high usability, we found the choice of AR or VR impacts mean search time (VR: 2.25s, AR: 3.92s) and mean direction estimation error (VR: 21.85°, AR: 32.91°). Moreover, while adding more out-of-view objects significantly affects search time across VR and AR, direction estimation performance remains unaffected. We provide implications and discuss the challenges of designing for VR and AR HMDs
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