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We present a search for the pair-production of a non-standard-model strongly-interacting particle that decays to a pair of quarks or gluons, leading to a final state with four hadronic jets. We consider both non-resonant production via an intermediate gluon as well as resonant production via a distinct non-standard-model intermediate strongly-interacting particle. We use data collected by the CDF experiment in proton-antiproton collisions at √ s = 1.96 TeV corresponding to an integrated luminosity of 6.6 fb −1 . We find the data to be consistent with standard model predictions. We report limits on σ(pp → jjjj) as a function of the masses of the hypothetical intermediate particles. Upper limits on the production cross sections for non-standard-model particles in several resonant and non-resonant processes are also derived.

Global burning velocities of methane-air-steam mixtures are measured on prismatic laminar Bunsen flames and lifted turbulent V-flames for various preheating temperatures, equivalence ratios and steam mixture fractions at atmospheric pressure. Experiments are conducted on a new rectangular slot-burner. Experimental burning velocities are compared to computed flame speeds of one dimensional adiabatic premixed flames using detailed mechanisms (Konnov 0.5 and GRI Mech 3.0). Mean profiles of radicals OH * are also extracted from these flames and compared to simulation results.

We search the COSMOS survey for pairs of galaxies consistent with the gravitational lensing signature of a cosmic string. The COSMOS survey imaged 1.64 square degrees using the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope (HST). Our technique includes estimates of the efficiency for finding the lensed galaxy pair. We find no evidence for cosmic strings with a mass per unit length of Gµ/c 2 < 3.0 × 10 −7 out to redshifts greater than 0.6 and set 95% upper limits. This corresponds to a global 95% upper limit of Ωstrings < 0.0028.

Some limitations of three dimensional Navier-Stokes Characteristic Boundary Conditions (3D-NSCBC) are discussed for flows traveling in a direction that is oblique to the boundary. To limit errors generated at boundaries with flows having any arbitrary direction, it is proposed to organize the wave decomposition in a coordinate system that is attached to the local flow streamline crossing the boundary, because some modeled expressions are not frame independent. Compared to previous 3D-NSCBC, the modified strategy accounting for oblique waves is found to improve the outflow treatment for transverse outgoing vortices, up to vortices crossing an outflow corner. The method is also applied to an expanding laminar flame.

SUMMARYA specific (hybrid) arrangement of variables is discussed to solve reactive compressible Navier-Stokes equations on staggered-like grids with high-order finite difference schemes. The objective is to improve the numerical flow solution at boundaries. Hybrid arrangement behaviour is compared with 'pure' colocated and staggered strategies. Classical Fourier analysis shows accuracy to be significantly improved in the hybrid case. One-dimensional laminar flame test demonstrates increased robustness (in terms of mesh resolution), whereas computation of 1D exiting pressure wave propagation gives evidence that the method also improves accuracy in the prediction of non-reflecting outflows, compared e.g. with the fully staggered scheme of (J. Comput. Phy. 2003). Multidimensional extension is illustrated through turbulent 2D planar and 3D expanding flames simulations.

Abstract. An implicit method based on high-order differentiation to determine the mean, Gaussian and principal curvatures of implicit surfaces from a three-dimensional scalar field is presented and assessed. The method also determines normal vectors and principal directions. Compared to explicit methods, the implicit approach shows robustness and improved accuracy to measure curvatures of implicit surfaces. This is evaluated on simple cases where curvature is known in closed-form. The method is applied to compute the curvatures of wrinkled flames on large triangular unstructured meshes (namely a 3D isosurface of temperature).

. Assessment of the Evolution Equation Modelling approach for threedimensional expanding wrinkled premixed flames. Combustion and Flame, Elsevier, 2012, 159 (5), pp.1932-1948. <10.1016/j.combustflame.2011 AbstractDirect Numerical Simulations (DNS), Evolution Equation Modelling (EEM) and Experimental results from the literature (EXP) are presented and analyzed for an expanding propane/air flame. DNS results are obtained thanks to the in-house finite-difference code HAllegro. Computed (DNS/EEM) and measured (EXP) equivalent radii R P and R S , mean stretch k and consumption velocity S C , as well as sample front shapes, are compared using to the same post-processing methodology. Small perturbations in the EEM input parameters induce comparatively small shifts in the compared results, showing the robustness of the approach. When slightly adapting only one O(1) parameter for the EEM strategy (the effective turbulent forcing amplitude felt by the flame), DNS and EEM show quite fair agreement one with the other and also with EXP, except for one of the experiments at early times. In the context of expanding flames, this validated EEM methodology can constitute a reliable tool to compute realisticly large sized flames.