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  1. Article ; Online: Modeling and correction of image drift in dynamic shadowgraphy experiments.

    Castellini, Stefano / Brizioli, Matteo / Giraudet, Cédric / Carpineti, Marina / Croccolo, Fabrizio / Giavazzi, Fabio / Vailati, Alberto

    The European physical journal. E, Soft matter

    2024  Volume 47, Issue 4, Page(s) 25

    Abstract: The study of phoretic transport phenomena under non-stationary conditions presents several challenges, mostly related to the stability of the experimental apparatus. This is particularly true when investigating with optical means the subtle temperature ... ...

    Abstract The study of phoretic transport phenomena under non-stationary conditions presents several challenges, mostly related to the stability of the experimental apparatus. This is particularly true when investigating with optical means the subtle temperature and concentration fluctuations that arise during diffusion processes, superimposed to the macroscopic state of the system. Under these conditions, the tenuous signal from fluctuations is easily altered by the presence of artifacts. Here, we address an experimental issue frequently reported in the investigation by means of dynamic shadowgraphy of the non-equilibrium fluctuations arising in liquid mixtures under non-stationary conditions, such as those arising after the imposition or removal of a thermal stress, where experiments show systematically the presence of a spurious contribution in the reconstructed structure function of the fluctuations, which depends quadratically from the time delay. We clarify the mechanisms responsible for this artifact, showing that it is caused by the imperfect alignment of the sample cell with respect to gravity, which couples the temporal evolution of the concentration profile within the sample with the optical signal collected by the shadowgraph diagnostics. We propose a data analysis protocol that enables disentangling the spurious contributions and the genuine dynamics of the fluctuations, which can be thus reliably reconstructed.
    Language English
    Publishing date 2024-04-08
    Publishing country France
    Document type Journal Article
    ZDB-ID 2004003-9
    ISSN 1292-895X ; 1292-8941
    ISSN (online) 1292-895X
    ISSN 1292-8941
    DOI 10.1140/epje/s10189-024-00413-y
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Dynamics of non-equilibrium concentration fluctuations during free-diffusion in highly stratified solutions of glycerol and water.

    Castellini, Stefano / Carpineti, Marina / Giraudet, Cédric / Croccolo, Fabrizio / Vailati, Alberto

    The Journal of chemical physics

    2023  Volume 158, Issue 24

    Abstract: We investigate the non-equilibrium fluctuations occurring during free diffusion between two solutions of glycerol and water with various concentration differences. The non-linearity of the system, determined by the strong stratification of the sample, ... ...

    Abstract We investigate the non-equilibrium fluctuations occurring during free diffusion between two solutions of glycerol and water with various concentration differences. The non-linearity of the system, determined by the strong stratification of the sample, requires introducing an interpretation model able to characterize the dependence of the correlation properties of the non-equilibrium fluctuations on the local thermophysical variables of the system. The proposed model allows us to characterize the dynamics of non-equilibrium fluctuations in the presence of a wide range of relaxation times determined by the strong stratification of the sample, at variance with the cumulant methods commonly used in dynamic light scattering experiments, which work well in the presence of a moderate dispersion of relaxation times.
    MeSH term(s) Water ; Glycerol ; Diffusion ; Solutions
    Chemical Substances Water (059QF0KO0R) ; Glycerol (PDC6A3C0OX) ; Solutions
    Language English
    Publishing date 2023-06-23
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3113-6
    ISSN 1089-7690 ; 0021-9606
    ISSN (online) 1089-7690
    ISSN 0021-9606
    DOI 10.1063/5.0151752
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Spreading of infections on random graphs: A percolation-type model for COVID-19.

    Croccolo, Fabrizio / Roman, H Eduardo

    Chaos, solitons, and fractals

    2020  Volume 139, Page(s) 110077

    Abstract: We introduce an epidemic spreading model on a network using concepts from percolation theory. The model is motivated by discussing the standard SIR model, with extensions to describe effects of lockdowns within a population. The underlying ideas and ... ...

    Abstract We introduce an epidemic spreading model on a network using concepts from percolation theory. The model is motivated by discussing the standard SIR model, with extensions to describe effects of lockdowns within a population. The underlying ideas and behaviour of the lattice model, implemented using the same lockdown scheme as for the SIR scheme, are discussed in detail and illustrated with extensive simulations. A comparison between both models is presented for the case of COVID-19 data from the USA. Both fits to the empirical data are very good, but some differences emerge between the two approaches which indicate the usefulness of having an alternative approach to the widespread SIR model.
    Keywords covid19
    Language English
    Publishing date 2020-07-03
    Publishing country England
    Document type Journal Article
    ZDB-ID 2003919-0
    ISSN 1873-2887 ; 0960-0779
    ISSN (online) 1873-2887
    ISSN 0960-0779
    DOI 10.1016/j.chaos.2020.110077
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Diffusion and convection in nature.

    Vailati, Alberto / Xu, Shenghua / Aime, Stefano / Croccolo, Fabrizio

    The European physical journal. E, Soft matter

    2021  Volume 44, Issue 12, Page(s) 145

    Abstract: We present the Topical Issue 'Diffusion and Convection in Nature'. ...

    Abstract We present the Topical Issue 'Diffusion and Convection in Nature'.
    Language English
    Publishing date 2021-11-30
    Publishing country France
    Document type Editorial
    ZDB-ID 2004003-9
    ISSN 1292-895X ; 1292-8941
    ISSN (online) 1292-895X
    ISSN 1292-8941
    DOI 10.1140/epje/s10189-021-00148-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: The modern structurator: increased performance for calculating the structure function.

    Norouzisadeh, Mojtaba / Chraga, Mohammed / Cerchiari, Giovanni / Croccolo, Fabrizio

    The European physical journal. E, Soft matter

    2021  Volume 44, Issue 12, Page(s) 146

    Abstract: The autocorrelation function is a statistical tool that is often combined with dynamic light scattering (DLS) techniques to investigate the dynamical behavior of the scattered light fluctuations in order to measure, for example, the diffusive behavior of ...

    Abstract The autocorrelation function is a statistical tool that is often combined with dynamic light scattering (DLS) techniques to investigate the dynamical behavior of the scattered light fluctuations in order to measure, for example, the diffusive behavior of transparent particles dispersed in a fluid. An alternative approach to the autocorrelation function for the analysis of DLS data has been proposed decades ago and consists of calculating the autocorrelation function starting from difference of the signal at different times by using the so-called structure function. The structure function approach has been proven to be more robust than the autocorrelation function method in terms of noise and drift rejection. Therefore, the structure function analysis has gained visibility, in particular in combination with imaging techniques such as dynamic shadowgraphy and differential dynamic microscopy. Here, we show how the calculation of the structure function over thousands of images, typical of such techniques, can be accelerated, with the aim of achieving real-time analysis. The acceleration is realized by taking advantage of the Wiener-Khinchin theorem, i.e., by calculating the difference of images through Fourier transform in time. The new algorithm was tested both on CPU and GPU hardware, showing that the acceleration is particularly large in the case of CPU.
    Language English
    Publishing date 2021-12-02
    Publishing country France
    Document type Journal Article
    ZDB-ID 2004003-9
    ISSN 1292-895X ; 1292-8941
    ISSN (online) 1292-895X
    ISSN 1292-8941
    DOI 10.1140/epje/s10189-021-00146-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Spreading of infections on random graphs

    Croccolo, Fabrizio / Roman, H. Eduardo

    Chaos, Solitons & Fractals

    A percolation-type model for COVID-19

    2020  Volume 139, Page(s) 110077

    Keywords General Mathematics ; covid19
    Language English
    Publisher Elsevier BV
    Publishing country us
    Document type Article ; Online
    ZDB-ID 2003919-0
    ISSN 1873-2887 ; 0960-0779
    ISSN (online) 1873-2887
    ISSN 0960-0779
    DOI 10.1016/j.chaos.2020.110077
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Topical Issue on Thermal Non-Equilibrium Phenomena in Soft Matter.

    Bresme, Fernando / Vesovic, Velisa / Bataller, Henri / Croccolo, Fabrizio

    The European physical journal. E, Soft matter

    2019  Volume 42, Issue 11, Page(s) 148

    Language English
    Publishing date 2019-11-22
    Publishing country France
    Document type Editorial
    ZDB-ID 2004003-9
    ISSN 1292-895X ; 1292-8941
    ISSN (online) 1292-895X
    ISSN 1292-8941
    DOI 10.1140/epje/i2019-11918-4
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Stabilized convection in a ternary mixture with two Soret coefficients of opposite sign.

    García-Fernández, Loreto / Bataller, Henri / Fruton, Paul / Giraudet, Cédric / Vailati, Alberto / Croccolo, Fabrizio

    The European physical journal. E, Soft matter

    2022  Volume 45, Issue 6, Page(s) 52

    Abstract: We performed ground-based experiments on the sample polystyrene-toluene-cyclohexane in order to complement the experimental activities in microgravity conditions related to the ESA projects DCMIX4 and Giant Fluctuations. After applying a stabilizing ... ...

    Abstract We performed ground-based experiments on the sample polystyrene-toluene-cyclohexane in order to complement the experimental activities in microgravity conditions related to the ESA projects DCMIX4 and Giant Fluctuations. After applying a stabilizing thermal gradient by heating from above a layer of the fluid mixture, we studied over many hours the density variations in the bidimensional horizontal field by means of a Shadowgraph optical setup. The resulting images evidence the appearance of convective instability after a diffusive time associated with the binary molecular solvent consisting of toluene and cyclohexane, confirming the negative sign of the Soret coefficient of this mixture. After a larger diffusive time related to mass diffusion of the polystyrene in the binary solvent, convection was suppressed by the increasing stabilizing density gradient originated by the Soret-induced concentration gradient of the polymer. This is compatible with a positive sign of the Soret coefficient of the polymer in the binary solvent.
    MeSH term(s) Convection ; Cyclohexanes ; Polymers ; Polystyrenes ; Solvents ; Toluene
    Chemical Substances Cyclohexanes ; Polymers ; Polystyrenes ; Solvents ; Toluene (3FPU23BG52)
    Language English
    Publishing date 2022-05-28
    Publishing country France
    Document type Journal Article
    ZDB-ID 2004003-9
    ISSN 1292-895X ; 1292-8941
    ISSN (online) 1292-895X
    ISSN 1292-8941
    DOI 10.1140/epje/s10189-022-00202-5
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: Spreading of infections on random graphs: A percolation-type model for COVID-19

    Croccolo, Fabrizio / Roman, H. Eduardo

    Chaos Solitons Fractals

    Abstract: We introduce an epidemic spreading model on a network using concepts from percolation theory. The model is motivated by discussing the standard SIR model, with extensions to describe effects of lockdowns within a population. The underlying ideas and ... ...

    Abstract We introduce an epidemic spreading model on a network using concepts from percolation theory. The model is motivated by discussing the standard SIR model, with extensions to describe effects of lockdowns within a population. The underlying ideas and behaviour of the lattice model, implemented using the same lockdown scheme as for the SIR scheme, are discussed in detail and illustrated with extensive simulations. A comparison between both models is presented for the case of COVID-19 data from the USA. Both fits to the empirical data are very good, but some differences emerge between the two approaches which indicate the usefulness of having an alternative approach to the widespread SIR model.
    Keywords covid19
    Publisher WHO
    Document type Article
    Note WHO #Covidence: #628252
    Database COVID19

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  10. Book ; Online: Spreading of infections on random graphs

    Croccolo, Fabrizio / Roman, H. Eduardo

    A percolation-type model for COVID-19

    2020  

    Abstract: We introduce an epidemic spreading model on a network using concepts from percolation theory. The model is motivated by discussing the standard SIR model, with extensions to describe effects of lockdowns within a population. The underlying ideas and ... ...

    Abstract We introduce an epidemic spreading model on a network using concepts from percolation theory. The model is motivated by discussing the standard SIR model, with extensions to describe effects of lockdowns within a population. The underlying ideas and behavior of the lattice model, implemented using the same lockdown scheme as for the SIR scheme, are discussed in detail and illustrated with extensive simulations. A comparison between both models is presented for the case of COVID-19 data from the USA. Both fits to the empirical data are very good, but some differences emerge between the two approaches which indicate the usefulness of having an alternative approach to the widespread SIR model.
    Keywords Physics - Physics and Society ; Quantitative Biology - Populations and Evolution ; covid19
    Publishing date 2020-06-01
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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