Urban air pollution by odor sources: Short time prediction

3noA numerical approach is proposed to predict the short time dispersion of odors in the urban environment. The model is based on (i) a three dimensional computational domain describing the urban topography at fine spatial scale (1 m) and on (ii) highly time resolved (1 min frequency) meteorological data used as in flow conditions. The time dependent, three dimensional wind velocity field is reconstructed in the Eulerian framework using a fast response finite volume solver of Navier-Stokes equations. Odor dispersion is calculated using a Lagrangian approach. An application of the model to the historic city of Verona (Italy) is presented. Results confirm that this type of odor dispersion simulations can be used (i) to assess the impact of odor emissions in urban areas and (ii) to evaluate the potential mitigation produced by odor abatement systems.openopenPettarin, Nicola; Campolo, Marina; Soldati, AlfredoPettarin, Nicola; Campolo, Marina; Soldati, Alfred

Two-Loop Quark Self-Energy in a New Formalism (II): Renormalization of the Quark Propagator in the Light-Cone Gauge

The complete two-loop correction to the quark propagator, consisting of the spider, rainbow, gluon bubble and quark bubble diagrams, is evaluated in the noncovariant light-cone gauge (lcg). (The overlapping self-energy diagram had already been computed.) The chief technical tools include the powerful matrix integration technique, the n^*-prescription for the spurious poles of 1/qn, and the detailed analysis of the boundary singularities in five- and six-dimensional parameter space. It is shown that the total divergent contribution to the two-loop correction Sigma_2 contains both covariant and noncovariant components, and is a local function of the external momentum p, even off the mass-shell, as all nonlocal divergent terms cancel exactly. Consequently, both the quark mass and field renormalizations are local. The structure of Sigma_2 implies a quark mass counterterm of the form $\delta m (lcg) = m\tilde\alpha_s C_F(3+\tilde\alpha_sW) + {\rm O} (\tilde\alpha_s^3)$, \tilde\alpha_s = g^2\Gamma(\eps)(4\pi)^{\eps -2}, with W depending only on the dimensional regulator epsilon, and on the numbers of colors and flavors. It turns out that \delta m(lcg) is identical to the mass counterterm in the general linear covariant gauge. Our results are in agreement with the Bassetto-Dalbosco-Soldati renormalization scheme.Comment: 36 pages Latex, 5 eps figures, to appear in Nucl.Phys.

Neutral Massive Spin 1/2 Particles Emission in a Rindler Spacetime

The Unruh effect for the rate of emission and absorption of neutral massive Majorana spinor particles -- the most plausible consituents of Dark Matter -- in a Rindler spacetime is thoroughly investigated. The corresponding Bogolyubov coefficients are explicitly calculated and the consistency with Fermi-Dirac statistics and the Pauli principle is actually verified.Comment: v2: clarifications added to Introduction and Conclusions, added appendices; v3 removed review part, published versio

Rockfall runout, Mount Cimone area, Emilia-Romagna Region, Italy

Numerous mass movements of different typology characterize both mountainous and piedmont sectors of the Emilia-Romagna Region (Apennine chain, North Italy). Although a less spatially frequent landslide typology within the region, rock falls represent severe threats to buildings, roads and persons due to their high propagation velocity. This paper presents an extract of the Emilia-Romagna regional map of the rock fall runout areas at a scale of 1:25,000. The analysis of rock fall runout areas was based upon a three-dimensional morphological method (TDM). The zone presented in the Main Map encompasses the area surrounding Mount Cimone, in the Emilia-Romagna Region. The proposed regional map of rockfall runout is noteworthy for planning actions and strategies aimed at the prevention and reduction of landslide risk at a regional scale

Veduta della Dogana di Terra a Piazza di Pietra

Questa fu fabbricata sulle rovine del Tempio di M. Aurelio Antonino Pio nel suo Foro 1. Avanzo di Colonne rimaste, oggi mezzo internate nella nuova Fabbrica 2. Architrave antico ristorato. 3. Cornicione, ed Ordine Attico nuovamente rifatto 4. Abitazione moderna 5. Collegio Bergumasco 6. Quartiere de Soldati. 7. Strada che va al Corso.https://digital.kenyon.edu/piranesi/1026/thumbnail.jp

Statistical properties of an ideal subgrid-scale correction for Lagrangian particle tracking in turbulent channel flow

One issue associated with the use of Large-Eddy Simulation (LES) to investigate the dispersion of small inertial particles in turbulent flows is the accuracy with which particle statistics and concentration can be reproduced. The motion of particles in LES fields may differ significantly from that observed in experiments or direct numerical simulation (DNS) because the force acting on the particles is not accurately estimated, due to the availability of the only filtered fluid velocity, and because errors accumulate in time leading to a progressive divergence of the trajectories. This may lead to different degrees of inaccuracy in the prediction of statistics and concentration. We identify herein an ideal subgrid correction of the a-priori LES fluid velocity seen by the particles in turbulent channel flow. This correction is computed by imposing that the trajectories of individual particles moving in filtered DNS fields exactly coincide with the particle trajectories in a DNS. In this way the errors introduced by filtering into the particle motion equations can be singled out and analyzed separately from those due to the progressive divergence of the trajectories. The subgrid correction term, and therefore the filtering error, is characterized in the present paper in terms of statistical moments. The effects of the particle inertia and of the filter type and width on the properties of the correction term are investigated.Comment: 15 pages,24 figures. Submitted to Journal of Physics: Conference Serie

Vat. copt. 57: A Codicological, Literary, and Paratextual Analysis

MS Vatican City, Biblioteca Apostolica Vaticana Vat. copt. 57, a collection of homi- lies attributed to John Chrysostom in Bohairic Coptic, poses a number of challenges to scholars. Questions such as, Can we identify the texts, and what is their rela- tionship to their Greek models? Can we know who the copyist(s) was or were? are approached by a team of scholars in a collaborative stud