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MODELLING THE INTERACTION OF PHYSICAL, CHEMICAL AND BIOLOGICAL PHENOMENA IN POROUS SOILS: A SUMMARY OF RESULTS
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A CELLULAR AUTOMATA MODEL OF SOIL BIOREMEDIATION
No full textThe remediation of contaminated soils is one of the major environmental problems in industrial countries today. Among the different techniques that can be applied, in situ bioremediation, which relies upon the use of indigeneous microorganisms to degrade the contaminant, is one of the most attractive, both from an environmental and an economic viewpoint.A full-scale bioremediation process requires a number of laboratory and pilot-scale tests in order to assess the feasibility of the remediation, to define potential health threats, and to find optimal operating conditions.Scaling up from the laboratory to the field can greatly benefit from the development of reliable mathematical models, which need to deal with several interacting physical, chemical, and biological phenomena.A macroscopic cellular automata (CA) model is presented here, which describes the major phenomena that take place in bioremediation. The reasons for using macroscopic CA are discussed. The model is composed of three layers, each layer depending on the others.The model has been tested in a pilot plant in the case of contamination by phenol. The values of the phenomenological parameters have been determined by the use of genetic algorithms (GAs). The model has provencapable of carefully describing experimental results for a wide range of experimental conditions. It is therefore an application of CA models to a real-world problem of high social and economic relevance
Selenite precipitation by a strain of Bacillus sp. in a sequencing batch system, potential application for wastewater treatment
No full textSCIDDICA-SS3: a new version of cellular automata model for simulating fast moving landslides
No full textCellular Automata (CA) are discrete and parallel computational models useful for simulating dynamic systems that evolve on the basis on local interactions. Some natural events, such as some types of landslides, fall into this type of phenomena and lend themselves well to be simulated with this approach. This paper describes the latest version of the SCIDDICA CA family models, specifically developed to simulate debris-flows type landslides. The latest model of the family, named SCIDDICA-SS3, inherits all the features of its predecessor, SCIDDICA-SS2, with the addition of a particular strategy to manage momentum. The introduction of the latter permits a better approximation of inertial effects that characterize some rapid debris flows. First simulations attempts of real landslides with SCIDDICA-SS3 have produced quite satisfactory results, comparable with the previous model.Cellular Automata (CA) are discrete and parallel computational models useful for simulating dynamic systems that evolve on the basis on local interactions. Some natural events, such as some types of landslides, fall into this type of phenomena and lend themselves well to be simulated with this approach. This paper describes the latest version of the SCIDDICA CA family models, specifically developed to simulate debris-flows type landslides. The latest model of the family, named SCIDDICA-SS3, inherits all the features of its predecessor, SCIDDICA-SS2, with the addition of a particular strategy to manage momentum. The introduction of the latter permits a better approximation of inertial effects that characterize some rapid debris flows. First simulations attempts of real landslides with SCIDDICA-SS3 have produced quite satisfactory results, comparable with the previous model
Microbial transformation of organic to inorganic lead, putative involvement of a soil bacterial community
No full textApplying cellular automata to complex environmental problems: the simulation of the bioremediation of contaminated soils
No full textCellular automata can be applied to modelling the dynamics of spatially extended physicalsystems, and represent an alternative to the classical PDE approach. In this paper a macroscopiccellular automata model for simulating the bioremediation of contaminated soils is introduced.The choice of macroscopic automata is motivated by the aim to simulate large-scale systems.It is suggested that in some cases, where the basic laws of continuum mechanics cannot bedirectly applied without adding phenomenological assumptions, and where the equation systemis not amenable to analytical solution, direct discrete modelling may represent a convenientalternative to the use of continuum models, followed by numerical discretization. This hypothesisis empirically tested in the bioremediation case.The model describes the bioremediation of contaminated soils, which relies upon the use ofindigeneous microorganisms to degrade the contaminant: bioremediation models pose particularchallenges as several physical, chemical and biological phenomena interact in a disordered andpartially unknown matrix (the soil). The model is hierarchical, and is composed by a fluiddynamical layer, a solute description layer and a biological layer. The model has been testedin a pilot plant, in the case of contamination by phenol. The values of the phenomenologicalparameters have been determined by the use of genetic algorithms. The model has proven capableto carefully describe experimental results in a wide range of experimental conditions. It has alsobeen run on a MIMD parallel architecture, achieving a high speed-up. It therefore representsan example of application of cellular automata to a real-world problem which has a very highsocial and economic importance, and where progresses in modelling may greatly improve theeffectiveness of the decontamination interventions
Modelling combined subaerial-subaqueous flow-like landslides by Macroscopic Cellular Automata
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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