197,744 research outputs found
Enhancing the performance of a parallel solver for turbulent reacting flow simulations
No full textThis article describes results of an effort to improve the parallel efficiency of a solver for turbulent reacting flows on two computer architectures. The compact finite-difference scheme employed for the solution of the differential equations involves the inversion of multiple tridiagonal matrices at each time step. Detailed performance evaluation of the standard LU, parallel partition LU, and parallel diagonal dominant algorithms are presented. The speed-up and efficiencies of these parallel strategies are critically compared and evaluated based on both computation and communication complexities, on the CRAY XT4 and IBM Blue Gene/P architectures.Mohamed Sayeed, Vinicio Magi, and John Abraha
Flame dynamics in the lift-off region of diesel jets
No full textIn this work, the large eddy simulation (LES) technique is employed to computationally model a lifted jet flame at conditions representative of those encountered in diesel engines. An unsteady flamelet progress variable (UFPV) model is used for turbulence/chemistry interactions. In the model, a look-up table of reaction source terms is generated as a function of mixture fraction Z, stoichiometric scalar dissipation rate χst, and progress variable Cst by solving the unsteady flamelet equations. In the present study, the progress variable is defined based on the sum of the major combustion products. A 37-species reduced chemical reaction mechanism for n-heptane is used to generate the UFPV libraries. The results show that ignition initiates at multiple points in the mixing layer around the jet, towards the edges of the jet, where the mixture fraction is rich, and the strain rates are within the ignition limits. These ignition kernels grow in time and merge to form a continuous flame front. Lift-off height is determined by the minimum axial distance from the orifice below whichthe local scalar dissipation rate does not favor ignition.Muhsin M. Ameen, Vinicio Magi, John Abrahamhttp://cfe.uwa.edu.au/news/acs2013http://www.anz-combustioninstitute.org
I magi zoroastriani e i segni dei tempi
No full textI magi nella cultura zoroastriana e il loro sapere iniziatico, divinatorio, predittivo e scrutatore di segni rivelatori di epoche e di avventi redentivi di Salvator
I Magi evangelici, Ciro il Grande e il Messia.
No full textL'articolo analizza il rapporto intercorrente tra le figure di Ciro il Grande, salutato come "L'unto del Signore" dal Deutero-Isaia, e Gesù, "Messia" per eccellenza, alla luce della vicenda dei Magi secondo le fonti tardo-antiche bizantine ed arabe. Lo studio prende inoltre in esame diverse figure delle storia biblica, in particolare quella di Melchisedeq, in rapporto con la leggenda della trasmissione ai Magi persiani (ed a Ciro) della profezia relativa alla nascita del salvatore
Magi is associated with lipid subdomains and alters PIP3 levels.
No full text(A-I) Cherry-tagged Magi (red) was expressed using apterous-GAL4 and accumulations within the basolateral region. (A-C) Magi::Cherry accumulations were positive for the ER marker Calnexin (green), arrows. (D-F) PIP3 (PH::GFP; green) was co-localized in the large accumulations (arrows) with Magi::Cherry. (G-I) Magi::Cherry accumulations were positive for Cholera toxin B (CTB, green)(arrows). (J-L) Endogenous Magi (red) colocalized with cholera toxin B (CTB, green) in wildtype discs at the plasma membrane. (M-S) Cherry-tagged Magi was overexpressed using apterous-GAL4 (ap>Magi::Cherry). The apterous boundary is indicated with a white line. (M-P) Wing imaginal discs overexpressing Magi::Cherry (red) with a PIP3 indicator (PH::GFP, green) under the control of the tubulin promoter. High levels of Magi resulted in an increase in of PIP3 at the plasma membrane. *** p<0.001; n = 5 discs. Error bars indicate SEM. (Q-S) Side projections showing the increase in PIP3 is within the apical domain (arrow) and within the large Magi accumulations (arrowhead). (T-Y) PTEN was expressed using apterous-GAL4 with Magi::Cherry (T-V) or without (W-Y). (T-V) Baz (green) was still displaced from the membrane when PTEN (blue) and Magi::Cherry (red) were coexpressed. (W-Y) Expression of PTEN alone had no effect on Magi recruitment to the membrane (arrowhead). Panels (A-L) were digitally magnified 200%. Scale bars indicate 5μm</p
SUPG Finite Element Formulation for a Two-Fluid Model
No full textThis paper presents a Finite Element model for incompressible laminar two-phase flows. A two-fluid model, describing the laminar non-equilibrium flow of two incompressible phases, is discretized by means of a properly designed SUPG finit element procedure consistent with a continuous pressure equation. The design and the implementationof the algorithm are presented together with its validation through a comparison with simulations available in literature
Variazioni climatiche, tettonica e sedimentazione al passaggio Pliocene Medio-Pliocene Superiore nel bacino del Valdarno Superiore (Appennino Settentrionale).
No full textStreamtube Model for Analysis of Vertical Axis Variable Pitch Turbine for Marine Currents Energy Conversion
No full textMarine currents may represent a renewable energy source characterized by a limited environmental impact. In Italy, the Strait of Messina seems to be suited for exploitation of this energy source. A vertical axis turbine, with blades oscillating about the pivotal axis according to the Voith–Schneider system, has been considered. This paper presents a preliminary theoretical investigation of the performance of this kind of turbine that may be employed to tap marine currents energy sources. The investigation is conducted by means of a simple momentum model based on the “single-disk single-streamtube” approach. The theoretical results are compared with experimental measurements. The adequate agreement between experimental and theoretical results shows that such a simple model may be able to predict the power coefficient and the operating range of the turbine
The Three Magi, the Stone of Christ and the Christian Origin of the Mazdean Fire Cult
No full textThe author discusses an important Uigur text about the three Magi of Bethlem, adding a number of improvements and interesting notes. The Uigur source, in fact, preserves the oldest version of the legendary aetiology of the Magian fire cult
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