112,028 research outputs found
Four loop stochastic perturbation theory in 3d SU(3)
No full textDi Renzo F, Mantovi A, Miccio V, Schroeder Y. Four loop stochastic perturbation theory in 3d SU(3). Nucl. Phys. Proc. Suppl. 2004;129-130:590-592
The leading non-perturbative coefficient in the weak-coupling expansion of hot QCD pressure
No full textDi Renzo F, Laine M, Miccio V, Schroeder Y, Torrero C. The leading non-perturbative coefficient in the weak-coupling expansion of hot QCD pressure. JHEP. 2006;2006(07):026.Using Numerical Stochastic Perturbation Theory within three-dimensional pure SU(3) gauge theory, we estimate the last unknown renormalization constant that is needed for converting the vacuum energy density of this model from lattice regularization to the MS scheme. Making use of a previous non-perturbative lattice measurement of the plaquette expectation value in three dimensions, this allows us to approximate the first non-perturbative coefficient that appears in the weak-coupling expansion of hot QCD pressure
Oil Painting of Joseph V. Miccio
No full text65 cm. long by 58 cm. wide, oil painting in wooden and fabric frame of Joseph V. Miccio. Gold plaque on frame gives the name. Painting by Peter Nicastro. Art inventory control number 843
3-d lattice QCD free energy to four loops
No full textDi Renzo F,, Mantovi A,, Miccio V,, Schroeder Y. 3-d lattice QCD free energy to four loops. JHEP. 2004;2004(05):006.We compute the expansion of the 3-d Lattice QCD free energy to four loop order by means of Numerical Stochastic Perturbation Theory. The first and second order are already known and are correctly reproduced. The third and fourth order coefficients are new results. The known logarithmic divergence in the fourth order is correctly identified. We comment on the relevance of our computation in the context of dimensionally reduced finite temperature QCD
3-d lattice SU(3) free energy to four loops
No full textDi Renzo F, Mantovi A, Miccio V, Schroeder Y, Torrero C. 3-d lattice SU(3) free energy to four loops. In: Nuclear Physics B - Proceedings Supplements. Nucl. Phys. Proc. Suppl. Vol 140. Elsevier BV; 2005: 586-588.We report on the perturbative computation of the 3d lattice Yang-Mills free energy to four loops by means of Numerical Stochastic Perturbation Theory. The known first and second orders have been correctly reproduced: the third and fourth order coefficients are new results and the known logarithmic IR divergence in the fourth order has been correctly identified. Progress is being made in switching to the gluon mass IR regularization and the related inclusion of the Faddeev-Popov determinant
Effect of system pressure on char combustion in Fluidized Beds. Model predictions
No full textAlthough Pressurized Fluidized Bed Combustion is already at the demonstration stage, fundamental studies on the effect of system pressure on the many aspects of the process are still under way. In this paper the effect of system pressure on fluidized bed char combustion is considered from a theoretical standpoint. Char combustion in bubbling fluidized bed is controlled by the oxygen transfer from bubbles to emulsion phase and from this latter to char particle surface, oxygen diffusion in the pore network and char intrinsic reactivity. According to previous indications this study confirms that the actual influence of system pressure on char combustion can only be deduced by means of a comprehensive mathematical model which accounts for the controlling steps altogether. The extention of a model previously developed by the authors to a pressure higher than atmospheric is finalized to this objective. This model is based on a char particle population balance and considers particle combustion, attrition and elutriation under simple bed fluid dynamics. With reference to a pre-pilot combustor, from which experimental data at atmospheric pressure were available, bed carbon loading, specific carbon combustion rate, characteristics resistances of the combustion mechanism and combustion efficiency have been calculated at a pressure of 12 bar and compared with results at 1 bar. In model evaluations, the excess air has been considered the main parametric variable. Different assumptions concerning bed fluid dynamics as well as combustion kinetics have been tested. Model results clearly indicate that bed carbon loading increases with pressure even though char combustion rate is faster due to higher oxygen partial pressure
Fluidized Bed Combustion of Liquid Bio-Fuels: Application of Integrated Diagnostics for Micro-Explosions Characterization
No full textA novel integrated diagnostic technique has been developed for the analysis of the “regime with microexplosions” that may be established during the low-temperature (T < 800 °C) fluidized bed combustion of liquid fuels. It consists of the comparison among three analogue data series: (i) pressure signals measured in the freeboard and high-pass filtered, (ii) oxygen molar fractions measured by zirconia-based probes at two elevations in the bed and in the splash region, and (iii) video frames of the bed surface recorded and purposely worked out. The integrated technique has been applied to the combustion of biodiesel at minimum fluidization and has proven to be a valid tool to provide the fingerprints of the mechanism of the low-temperature fluidized combustion of liquid fuels. The time series generated from the measured data sets have been analyzed with the aid of the Hurst’s rescaled range analysis, the V-statistic, and the Lyapunov exponents’ evaluation. The issue of localizing micro-explosions throughout bed, bubbles, and splash zone has been tackled by the V-statistic analysis, which has proven that the location of micro-explosions is just at the bed surface when T = 650 °C and moves deeper and deeper into the bed when its temperature increased to about 800 °C. The values found
for the largest Lyapunov exponent in the time series demonstrate that the investigated system is not only
dynamic but also chaotic in its nature
On the mutual interaction that salt and water have on meat-derived products in a closely-controlled pilot chamber
No full text- …
