The technical recommendations in the design of stacks indicate that the emission at higher height, or a greater exhaust speed gases, decreases the impact in the surroundings. In fact, it is usual increases stack height in problematic sources.

   Taking into account this principle, additional propulsion systems for conducted sources have been designed. This type of technology allows to power the exhaust gases at a high speed, diluting simultaneously with a high flow rate, and minimizing the impact on the environment.

A. Amo, R. Cerdá, M.A. Cid, J.V. Martínez

Labaqua S.A. Alicante, Spain.

   The Graz Lagrangian (GRAL) system is a Lagrangian particle model with a free Graphic User Interface (GUI) available in both Linux and Windows. The last beta was published last November and now the developers have released the version 20.01. The software is now open source under a GPL-3.0 license, so everybody is welcomed to contribute to the project. The source code, has been published in github.

    The Graz Lagrangian Model - GRAL - was initially developed in 1999, and has been used extensively in regulatory assessments and scientific studies. The initial driver for the development of GRAL was the need for a model that could deal with the frequent low-wind-speed conditions (< 1.5 m s^-1 for up to 90 per cent of the time) in the inner-Alpine basins of Austria. According to the developers, there are around 600 users worldwide using, the GRAL/GRAMM system.