Marco T. Vilhena

Air pollution and turbulence : modeling and applications

Deposition, Transformation, and Remobilization of Soot and Diesel Particulates on Building Surfaces, P. Brimblecombe and C.M. Grossi Atmospheric Boundary Layer: Concepts and Measurements, G. Fisch Turbulence and Dispersion of Contaminants in the Planetary Boundary Layer, G.A. Degrazia, A. Gledson Oliveira Goulart, and D.R. Roberti Parameterization of Convective Boundary Layer Turbulence and Clouds in Atmospheric Models, P.M.M. Soares, J. Teixeira, and P.M.A. Miranda Mathematical Air Pollution Models: Eulerian Models, T. Tirabassi Analytical Models for the Dispersion of Pollutants in Low Wind Conditions, P. Kumar and M. Sharan On the GILTT Formulation for Pollutant Dispersion Simulation in the Atmospheric Boundary Layer, D.M. Moreira, M. Tullio M. B. de Vilhena, and D. Buske An Outline of Lagrangian Stochastic Dispersion Models, D. Anfossi and S.T. Castelli Atmospheric Dispersion with a Large-Eddy Simulation: Eulerian and Lagrangian Perspectives, U. Rizza, G. Gioia, G. Lacorata, C. Mangia, and G.P. Marra Photochemical Air Pollution Modeling: Toward Better Air Quality Management, C. Borrego, A.I. Miranda, and J. Ferreira Inversion of Atmospheric CO2 Concentrations, I.G. Enting Index

Estimation of boundary condition in hydrologic optics

A reconstruction technique for estimating boundary conditions in natural waters from in situ radiance data is presented. The inverse problem is formulated as a nonlinear constrained optimization problem. The objective function is defined as the square Euclidean norm of the difference vector between experimental and computed data. The associated direct problem is solved by LTSN method.

Non-Linear Radiative-Conductive Heat Transfer in a Heterogeneous Gray Plane-Parallel Participating Medium

Radiative transfer considers problems that involve the physical phenomenon of energy transfer by radiation in media. These phenomena occur in a variety of realms (Ahmad & Deering, 1992; Tsai & Ozisik, 1989; Wilson & Sen, 1986; Yi et al., 1996) including optics (Liu et al., 2006), astrophysics (Pinte et al., 2009), atmospheric science (Thomas & Stamnes, 2002), remote sensing (Shabanov et al., 2007) and engineering applications like heat transport by radiation (Brewster, 1992) for instance or radiative transfer laser applications (Kim & Guo, 2004). Furthermore, applications to other media such as biological tissue, powders, paints among others may be found in the literature (see ref. (Yang & Kruse, 2004) and references therein). Although radiation in its basic form is understood as a photon flux that requires a stochastic approach taking into account local microscopic interactions of a photon ensemble with some target particles like atoms, molecules, or effective micro-particles such as impurities, this scenario may be conveniently modelled by a radiation field, i.e. a radiation intensity, in a continuous medium where a microscopic structure is hidden in effective model parameters, to be specified later. The propagation of radiation through a homogeneous or heterogeneous medium suffers changes by several isotropic or non-isotropic processes like absorption, emission and scattering, respectively, that enter the mathematical approach in form of a non-linear radiative transfer equation. The non-linearity of the equation originates from a local thermal description using the Stefan-Boltzmann law that is related to heat transport by radiation which in turn is related to the radiation intensity and renders the radiative transfer problem a radiative-conductive one (Ozisik, 1973; Pomraning, 2005). Here, local thermal description means, that the domain where a temperature is attributed to, is sufficiently large in order to allow for the definition of a temperature, i.e. a local radiative equilibrium. The principal quantity of interest is the intensity I, that describes the radiation energy flow through an infinitesimal oriented area dΣ = ndΣ with outward normal vector n into the solid angle dΩ = ΩdΩ, where Ω represents the direction of the flow considered, with angle θ of the normal vector and the flow direction n · Ω = cos θ = μ. In the present case we focus on the non-linearity of the radiative-conductive transfer problem and therefore introduce the simplification of an integrated spectral intensity over all wavelengths or equivalently all frequencies that contribute to the radiation flow and further ignore possible effects due to polarization. Also possible effects that need in the formalism properties such as coherence 8

Analytical solution for the AN approximation

The aim of this work consists of the presentation of a new derivation and also an analytical solution for the one-dimensional AN approximation of the linear transport equation. Numerical simulations are reported.

Inversion of Higher-Order Matrix Difference and Differential Equations through Their Dynamical Solutions

Abstract We discuss matrix finite difference and ordinary differential equations in terms of their dynamical solutions which correspond to Green functions for initial-value problems. Explicit formulas, which make no use of Jordan decompositions, are derived by using the Laplace-Stieltjes transform. The situation for inverting matrix polynomials is also considered.

ON A CLOSED FORM SOLUTION OF THE POINT KINETICS EQUATIONS WITH REACTIVITY FEEDBACK OF TEMPERATURE

An analytical solution of the point kinetics equations to calculate time-dependent reactivity by the decomposition method has recently appeared in the literature. In this paper, we consider the neutron point kinetics equations together with temperature feedback effects. To this end, point kinetics is perturbed by a temperature equation that depends on the neutron density, obtaining a second-order non-linear ordinary differential equation. This equation is then solved by the decomposition method by expanding the neutron density in a series and expressing the non-linear terms by Adomian polynomials. Upon substituting these expansions into the non-linear ordinary equation, we construct a recursive set of linear problems that can be solved and resulting in an exact analytical representation for the solution. We also report numerical simulations and comparison against literature results.

A General Lagrangian Approach to Simulate Pollutant Dispersion in Atmosphere for Low-wind Condition

In this work we present a semi-analytical Lagrangian particle model to simu late the pollutant dispersion during low wind speed conditions. The model is based on a methodology, which solves the Langevin equation through the assumption that coefficient of the integrating factor is a complex function. The method leads to a non-linear stochastic integral equation, which is solved by the Method of Successive Approximations or Picards Iterat ive Method. Taking into account the isomorphis m between the co mp lex and real p lane by writing down the low wind fo rmulat ion in polar form, the procedure allow to determine a formu la for the lo w wind direction. Furthermo re, an exp ression analogous to the Eulerian autocorrelation function suggested by Frenkiel(1) appears in the real co mponent solution. The model results present an improvement in relat ion to the other models and are shown to agree very well with the field tracer data collected during stable conditions at Idaho National Engineering Laboratory (INEL).

Modelagem da Dispersão de Poluentes na Atmosfera Considerando uma Fonte Móvel

O presente trabalho refere-se ao problema de dispersao de poluentes na atmosfera com a emissao realizada atraves de uma fonte movel. Para representar este fenomeno, apresenta-se um novo modelo matematico que utiliza a equacao da adveccao-difusao. Resolve-se esta equacao atraves do metodo GILTT (Generalized Integral Laplace Transform Technique) e utiliza-se o experimento de OLAD (Over-Land Atmospheric Dispersion) para simulacao. Os resultados obtidos ressaltam a capacidade do modelo em representar o comportamento da dispersao presente no experimento.

Modelo para dispersão de poluentes na atmosfera com condições de contorno parcialmente reflexivas

A equacao de adveccao-difusao modela o fenomeno de dispersao de poluentes na camada limite atmosferica. Tal equacao com fechamento Fickiano para turbulencia e coeficientes de difusao Kx, Ky e Kz constantes [...]

On a Model for Pollutant Dispersion in the Atmosphere with Partially Reflective Boundary Conditions

The present work is an attempt to simulate the dispersion of pollutants in the surroundings of the thermoelectric plant located in Linhares from a new mathematical model based on partially reflective boundaries in the deterministic advection-diffusion equation. In addition to the advection-diffusion equation with partially reflective boundaries, it was used data simulated with the CALPUFF model. The exposed model was validated previously with the Hanford and Copenhagen experiments and the results indicate that effects on the boundaries are essential to model dispersion phenomenona in the atmospheric boundary layer.