286 research outputs found
Supporting Higher Education—Hospital Transition through Blended Learning
The purpose of this paper is to present two exploratory studies that have a potential for identifying research-based blended learning tools for CBME. The studies focus on the development of a group of medical students’ professional image (in Genova and Rome) during their hospital internship. The paper addresses three related questions:
1. How does their professional representation change in the transition from university to hospital?
2. Which competences emerge from the students’ reports?
3. Which competences are still under represented
Multispecies reactive transport modelling of electrokinetic remediation of harbour sediments
We implemented a numerical model to simulate transport of multiple species and geochemical reactions occurring during electrokinetic remediation of metal-contaminated porous media. The main phenomena described by the model were: (1) species transport by diffusion, electromigration and electroosmosis, (2) pH-dependent buffering of H+, (3) adsorption of metals onto particle surfaces, (4) aqueous speciation, (5) formation and dissolution of solid precipitates. The model was applied to simulate the electrokinetic extraction of heavy metals (Pb, Zn and Ni) from marine harbour sediments, characterized by a heterogeneous solid matrix, high buffering capacity and aged pollution. A good agreement was found between simulations of pH, electroosmotic flow and experimental results. The predicted residual metal concentrations in the sediment were also close to experimental profiles for all of the investigated metals. Some removal overestimation was observed in the regions close to the anode, possibly due to the significant metal content bound to residual fraction
Resistivity imaging during electrokinetic remediation of sediments: practical challenges in the field
The use of geophysical techniques such as electrical resistivity and impedance tomography have proven to be
effective for the investigation and monitoring of a variety of environmental processes.
This study investigates the possibility of using resistivity imaging to monitor the progress of electrokinetic
remediation, a decontamination process based on electrochemical methods.
The resistivity is a parameter of great theoretical and practical interest. On one side, resistivity is strictly related
to the pore fluid composition and provides information about the chemical state of the material subjected to
remediation. On the other side, knowing the evolution and distribution of resistivity is of practical importance both
at the design stage and during operation because it directly affects the electrical energy expenditures.
Monitoring of electrokinetic processes both in laboratory and in field is usually carried out by point measure-
ments and sample collection from discrete locations. Resistivity imaging is effective in providing low-cost,
non-destructive, high space and time resolution mapping.
During electrokinetic remediation an electric field is applied to the contaminated matrix to extract the pollutants.
In the field, array of electrodes are generally employed to apply the electric field, arranged in a two-dimensional
grid. The electrodes are installed inside wells to allow the circulation of electrolytes employed to enhance the
extraction of the pollutants.
In this study we describe the practical challenges both in the measurements and in the data processing encountered
during the tomographic imaging of marine sediments subjected to electrokinetic remediation in a 150 m3 ex-situ
treatment plant.
In such system there are a number of constraints to overcome in order to obtain an effective tomographic image
of the sediments: (1) the electric field applied for remediation cannot be powered off, thus this field represents
the source for current injection for the resistivity measurements, (2) the applied electric field signal is irregular
and noisy because it is generated by high power current regulators, (3) the environment is extremely corrosive and
special care must be taken choosing the electrode material, (4) a number of disturbances, such as the influence of
the wells and pipes on the electric field distribution must be taken into account, (5) the electric field is generated
by all the electrode couples operating simultaneously (the current injection is produced by multiple electrodes)
Modeling of Electrokinetic Remediation Combining Local Chemical Equilibrium and Chemical Reaction Kinetics
A mathematical model for reactive-transport processes in porous media is presented. The modeled system includes diffusion, electromigration and electroosmosis as the most relevant transport mechanism and water electrolysis at the electrodes, aqueous species complexation, precipitation and dissolution as the chemical reactions taken place during the treatment time. The model is based on the local chemical equilibrium for most of the reversible chemical reactions occurring in the process. As a novel enhancement of previous models, the local chemical equilibrium reactive-transport model is combined with the solution of the transient equations for the kinetics of those chemical reactions that have representative rates in the same order than the transport mechanisms.
The model is validated by comparison of simulation and experimental results for an acid- enhanced electrokinetic treatment of a real Pb-contaminated calcareous soil. The kinetics of the main pH buffering process, the calcite dissolution, was defined by a simplified empirical kinetic law. Results show that the evaluation of kinetic rate entails a significant improvement of the model prediction capability.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045. Part of this work was supported financially by the European Commission within the project LIFE12 ENV/IT/442 SEKRET “Sediment electrokinetic remediation technology for heavy metal pollution removal”. Paz-Garcia acknowledges the financial support from the “Proyecto Puente - Plan Propio de Investigación y Transferencia de la Universidad de Málaga”, code: PPIT.UMA.B5.2018/17. Villen-Guzman acknowledges the financial support from the University of Malaga through a postdoctoral contract
Influence of chemical reaction kinetics on electrokinetic remediation modelling results
A numerical model describing transport of multiple species and chemical reactions during
electrokinetic treatment is presented. The transport mechanisms included in the model were
electromigration and electroosmosis. The chemical reactions taken into account were water
electrolysis at the electrodes, aqueous species complexation, precipitation, and dissolution.
The model was applied to simulate experimental data from an acid-enhanced electrokinetic
treatment of a Pb-contaminated calcareous soil. The kinetics of the main pH buffering process
(i.e., calcite dissolution) was taken into account and its time-dependent behavior was described
by a rate law. The influence of kinetics was evaluated by comparing the results from a set of
simulations in which calcite dissolution was implemented considering thermodynamic
equilibrium and another set in which the same reaction was described by the rate law. The results
show that the prediction capability of the model significantly improves when the kinetic rate is
taken into account.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Collisions of self-bound quantum droplets
We report on the study of binary collisions between quantum droplets formed
by an attractive mixture of ultracold atoms. We distinguish two main outcomes
of the collision, i.e. merging and separation, depending on the velocity of the
colliding pair. The critical velocity that discriminates between the two
cases displays a different dependence on the atom number for small and
large droplets. By comparing our experimental results with numerical
simulations, we show that the non-monotonic behavior of is due to the
crossover from a compressible to an incompressible regime, where the
collisional dynamics is governed by different energy scales, i.e. the droplet
binding energy and the surface tension. These results also provide the first
evidence of the liquid-like nature of quantum droplets in the large limit,
where their behavior closely resembles that of classical liquid droplets
Strumenti per promuovere la riflessione sull'esperienza professionale: il Situational Judgment Test
What tools are available to support reflection by trainees on professional practices? The paper presents the Situational Judgment Test, a method that is being used in the selection of personnel and that we adapted to be of support to higher education Medicine students during their internship. The paper outlines the tool’s features and its planning phases. It focuses on the potential for critical incidents to elicit reflection on the mindsets and mental frames that are conditioning the professional agency.Quali strumenti sono in grado di promuovere processi riflessivi sulle pratiche professionali dei professionisti in formazione? L’articolo presenta il Situational Judgment Test, metodo utilizzato nella selezione del personale, in una sua applicazione con studenti di Medicina impegnati nel tirocinio ospedaliero. Dopo aver presentato lo strumento e descritto le fasi per la progettazione del test, viene sottolineato il ruolo che la relazione tra riflessione e incidenti critici gioca nel processo di esplicitazione delle cornici di senso che condizionano l’agire professionale
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