Mathematical modeling and simulation of volatile reduced sulfur compounds oxidation in biotrickling filters

[Abstract] The odour generated by industrial gaseous emissions causing nuisances generally is due to the presence of volatile reduced sulfur compounds (VRSC) Although a number of microorganisms are known for degrading VRSC, the treatment of a mixture of reduced sulfur compounds remains challenging for several reasons. To resolve these problems two-stage systems have been proposed, in the first reactor H2S is bio-oxidized and in the second the rest of the VRSC mixture, avoiding the inhibition effects of H2S over the bio-oxidation of these compounds. In the systems described the complete oxidation of H2S must be performed in the first reactor, if some H2S pass though out the first reactor it would have an effect on the bio-oxidation of the other VRSC present in the mixture in the second bioreactor. This situation was modelled and simulated, and is presented in this article. The bio-oxidation of H2S and DMS in a biotrickling filter is described through a model of the mass transfer and chemical reaction processes. The biotrickling filter is modeled as a fixed bed of packing material which supports the growth of micro-organisms as biofilms. When air flows in the bed, H2S and DMS are continuously transferred from the gas phase to the biofilm, where they diffuse and are oxidized by aerobic microbial activity. A summary of the equations, results of the simulation and sensibility to the inhibition constants are reported

Coevolution of dynamical states and interactions in dynamic networks

We explore the coupled dynamics of the internal states of a set of interacting elements and the network of interactions among them. Interactions are modeled by a spatial game and the network of interaction links evolves adapting to the outcome of the game. As an example we consider a model of cooperation, where the adaptation is shown to facilitate the formation of a hierarchical interaction network that sustains a highly cooperative stationary state. The resulting network has the characteristics of a small world network when a mechanism of local neighbor selection is introduced in the adaptive network dynamics. The highly connected nodes in the hierarchical structure of the network play a leading role in the stability of the network. Perturbations acting on the state of these special nodes trigger global avalanches leading to complete network reorganization.Comment: 4 pages, 5 figures, for related material visit http:www.imedea.uib.es/physdept

Demonstration of Elemental Partitioning During Austenite Formation in Low-Carbon Aluminium alloyed steel

This work investigates the influence of aluminium, in solid solution, on austenite formation in a lowcarbon aluminium alloyed (0.48 wt. %) steel during continuous heating. A thin section across an untransformed ferrite and austenite interface was prepared for transmission electron microscopy by focused ion beam milling. Microstructural characterization using imaging and elemental analysis demonstrates that aluminium partitions from austenite to ferrite during very slow heating conditions, stabilizing this latter phase and shifting the final transformation temperature for austenite formation (Ac3)Peer reviewe

Demonstration of Elemental Partitioning During Austenite Formation in Low-Carbon Aluminium alloyed steel

This work investigates the influence of aluminium, in solid solution, on austenite formation in a lowcarbon aluminium alloyed (0.48 wt. %) steel during continuous heating. A thin section across an untransformed ferrite and austenite interface was prepared for transmission electron microscopy by focused ion beam milling. Microstructural characterization using imaging and elemental analysis demonstrates that aluminium partitions from austenite to ferrite during very slow heating conditions, stabilizing this latter phase and shifting the final transformation temperature for austenite formation (Ac3)Peer reviewe

An Experience in Integrated Knowledge about Manufacturing Technologies for Students of the Grades of Industrial Engineering

AbstractIn the development of the specific skills in the field of industrial engineering, the transversality of the contents of each area of knowledge must be considered. This paper shows how the integration of the contents of different areas (such as materials, manufacturing, design, etc.) is performed in order to allow students to enhance their transversal skills. For this, a specific product is proposed as “learning object”. The analysis, to be made by the students, includes all the aspects regarding technical and economic feasibility, and manufacturing optimization of the product. The article also shows the analysis of the work environment and the established methodology by an interdisciplinary group of university teachers from different areas: materials, manufacturing and design who have contributed with their knowledge in the specific problem