Arnaud Sapin

Psychologue Social

Ghozlane Fleury-Bahi

Provence

De la planète à l'assiette : l'effet médiateur de la connexion à la nature sur le lien entre attitude et alimentation écologique

EXPLIQUER LES COMPORTEMENTS ALIMENTAIRES

→ Attitudes à l'égard de l'environnement

• Prédicteur de la consommation réduite de viande (Garça et al., 2015 ;Lentz et al., 2018) • Prédicteur de la consommation de produits issus de l'agriculture biologique (Cabuk et al., 2014;Scalco et al., 2017) → Connexion à la nature • Prédicteur des comportements écologiques en général (Barrera-Hernández et al., 2020) • Prédicteur des comportements alimentaires écologiques (Spendrup et al., 2016;Baldi et al., 2021) • Pas d'étude sur le caractère médiateur de la connexion !

attitudes vis-à-vis du bénéfice environnemental de l'alimentation et les comportements alimentaire écologiques METHODES : OUTILS Connectedness To Nature Scale Version Française : Navarro

  , Olivos etFleury-Bahi (2017)

Hypothèse de recherche : La connexion à la nature médiatise le lien entre les

Inventaire de comportements alimentaires écologiques et Inventaire d'attitudes à l'égard du bénéfice environnemental l'alimentation écologique

  La connexion à la nature apporte de l'information sur le lien attitude-comportement pour les comportements de choix de produits mais pas de privation alimentaires !

	METHODES : OUTILS ET PARTICIPANTS RESULTATS : MODELE D'EQUATION STRUCTURAL D I S C U S S I O N Annexe
	Population : 1058 participants	N	%
	Genre
	Comportements alimentaires écologiques Dimension 1: Choix de produits 1. Je consomme des aliments produits localement (moins de 100 kilomètres de mon domicile) 2. Je consomme des aliments produits en France 3. J'achète mes aliments directement au producteur ou dans des marchés 4. Je consomme des aliments biologiques 5. Je consomme des aliments issus du commerce equitable 6. Je fais attention à ne consommer que des fruits ou légumes de saison 7. J'évite de consommer des aliments très emballés Dimension 2 : Restrictions alimentaires 8. Je consomme de la viande (I) Homme Femme Autre / Pas de réponse Attitudes à l'égard du bénéfice environnemental de l'alimentation 299 28.3% Dimension 1: Choix de produits 1. Consommer des aliments produits localement 2. Consommer des aliments produits en France 3. Acheter ses aliments directement au producteur 4. Consommer des aliments « biologiques » 5. Consommer des aliments issus du commerce equitable 6. Consommer des fruits ou légumes de saison 7. Eviter de consommer des aliments très emballés Dimension 2 : Restrictions alimentaires 9. Consommer moins de poisson 8. Consommer moins de viande 10. Consommer moins de produits laitiers et d'oeufs 750 70.9% 9 .9% Adhésion à une AMAP Oui 183 17.3% Non 873 82.5% Pas de réponse 2 .2% Régime alimentaire Omnivore 504 47.6% Flexitarien/ne 372 35.2% Végétarien/ne 129 12.2% Végétalien/ne -Végan/e 49 4.6% Pas de réponse 4 .4% Âge M=34.8 SD=11.9 Aisance financière M=3.52 SD=1.5 Indicateurs de fit CFI 0.942 TLI 0.935 RMSEA 0.057 SRMR 0.065 Perspective d'application : la pertinence de mobiliser la connexion à la nature dépend donc du comportement alimentaire ciblé ! Moyenne Ecart-type Médiane Comportements -Global 3.49 .533 3.50 Comportement -D1 3.74 .595 3.78 Comportement-D2 2.76 .942 2.67 Merci de votre Attitude -global 4.18 .563 4.27 Attitude -D1 4.33 .555 4.38 Attitude -D2 3.77 .957 4.00 attention ! CNS 3.93 .704 4.00
	9. Je consomme du poisson (I)
	10. Je consomme des produits laitiers et des oeufs (I) Procédure : Diffusion sur des groupes thématiques sur les réseaux sociaux

Echelles ad-hoc conçue dans l'étude à partir des échelles anglophones et d'une pré-étude de 6 entretiens Analyse factorielle exploratoire (1/3 échantillon) + confirmatoire (2/3 échantillon) Comportements : CFI=.933 ; TLI=.912. Attitudes : CFI=.948 ; TLI=.931. Dissociation entre comportements de choix de produits et restriction alimentaire METHODES : OUTILS L'hypothèse est partiellement validée :


Denis Jullien

Adeline Payet

Emmanuelle Guillou

Henri-Marc Bourbon

Sandra Bernat- Fabre

Muriel Boube-Trey

Henri- Marc Bourbon

Sandra Bernat

Auxin-induced (AID) protein degradation in drosophila larvae

Keywords: AID, Auxininduced degradation, NAA, targeted protein degradation, drosophila Funders

The present protocol describes how to operate the auxin degradation system in drosophila larvae.The auxin-induced degradation, also referred to as AID, is an efficient targeted protein degradation system widely used in many model organisms. Thanks to the fact that fast degradation is triggered once a small molecule, the auxin, is added to the cell environment, a tight temporal control of the loss of a protein of interest can be achieved. This unique control of when the proteolysis is triggered allows to study the precocious consequences of the loss of function. Importantly, the implementation of this protocol requires genetically modified flies that express the auxin-dependent F-box protein TIR1, usually under the control of the UAS/Gal4 system to achieve a spatial control of the degradation, and in which the AID degron has been inserted (typically using CRISPR) to the coding sequence of the gene of interest. The problem raised by the use of the AID system in drosophila larvae, as in all the metazoans that have thick tegument, is the penetration of the auxin to each indidual cell of the organism. Here we present a non-invasive strategy based on the ingestion by the larva of a nutritive medium that contains auxin. We detail how to prepare the auxin containing food, handle the larvae, and which food container to use. Our method allows a fast degradation in the imaginal discs, as early as 30 minutes after the larvae were transfered to the auxin containing medium, with little inter-individual difference.

protocols.

GUIDELINES

The method described here to induce targeted protein degradation with the AID system in drosophila larva is based on feeding the animal with auxin containing nutritive medium. Once present in the digestive asparatus, auxin penetrates in the tissues of the larva.

The protocol workflow is: Day 1: young well-fed adults are transfered to fresh fly tubes.

Allow the flies to lay eggs for 15 hours, then remove the adults from the tube. This allow to get larvae all at a similar stage, and also avoid overcrowding.

Day 3: prepare auxin containing petri dishes 30 mm plastic petri dishes containing a nutritive medium that contains auxin need to prepared.

Day 4 to day 5: collect larvae and trigger protein degradation, and proceed to phenotype analysis. To trigger protein degradation, larvae are transfered using forceps to the auxin dishes. Step 3.3

MATERIALS

SAFETY WARNINGS

For hazard information and safety warnings, please refer to the SDS (Safety Data Sheet).

Auxin is toxic when used on cells above 50 mM.

BEFORE START INSTRUCTIONS

Genetically modified flies need to be generated before the present protocol can be implemented. These flies should contain:

1) a transgene allowing the expression of the auxin-dependent F-box protein TIR1, usually under the control of the UAS/Gal4 system (to achieve a spatial control of the degradation), 2) the AID degron inserted (typically using CRISPR) to the coding sequence of the gene of interest. See materials for an illustrative figure.

.

Note

In our hands, we found it is time saving to initially invest in generating genetic setups that are ready to use in term of induction of protein degradation by auxin (no crosses required to generate the larvae with the right genetic background allowing the AID system to work). As an example, in the case of degradation of Med19-AID (3rd chromosome), we recombined the UASt::TIR1 transgene (3rd Chromosome) with the Med19-AID allele, and use the 2nd chromosome to carry the Gal4 driver. For instance, for a degradation of Med19-AID directed in the posterior domain of the wing imaginal disc, the genotype for a ready to use system is enGal4; Med19-AID-GFP, UAStTIR1 (see materials for a figure).

1.1

Transfer in standard wheat cornmeal fly tubes about 50 healthy young adult flies (1/3 males, 2/3 females) per tube

Note

See the fly genotype required at this step in the previous note. It is essential to perform a no degradation control. Proper fashions to do so include using an identical genotype except that:

possibility 1) it is devoid of the gal4 driver, or possibility 2) the gene of interest is devoid of the AID degron.

1.2

Let the flies lay eggs Overnight at 25 °C

1.3

Remove the flies from the tubes

  acid Sigma-aldrich Catalog #N0640 protocols.io | https://dx.doi.org/10.17504/protocols.io.www.finescience.com/en-US/Products/Forceps-Hemostats/Dumont-Forceps/Dumont-5-Forceps/11251-10 LINK protocols.io | https://dx.doi.org/10.17504/protocols.io.kqdg3949pg25/v1 Oct 16 2022 4 Genetic and molecular set-up used for the AID-mediated degradation of Med19 in drosophila. The expression of the auxin-dependent and AIDspecific F-box protein TIR1 is controlled by the UAS/Gal4 system. The Gal4 driver is located in the second chromosome, when the UAS::TIR1 is positioned to the third chromosome where the Med19* gene lies. The Fbox TIR1 incorporates the endogenous SCF (Skip1 Cul1 F-box) E3 ubiquitin complex c. Auxin (added to the fly food) triggers polyubiquitination of Med19* by the SCFTIR1 targeting the Mediator subunit to degradation by the proteasome. protocols.io | https://dx.doi.org/10.17504/protocols.io.kqdg3949pg25

  dx.doi.org/10.17504/protocols.io.kqdg3949pg25/v1 Oct 16 2022 6

  dx.doi.org/10.17504/protocols.io.kqdg3949pg25/v1 Oct 16 2022

Agence Nationale de Recherche Grant ID: ANR-16 CE12-0021-01

Schematic view of the protocol used to operate the AID system in drosophila larvae. Here, a genetic configuration where the expression of TIR1 is driven by the Ubiquitin promoter is shown.

Note

NAA (1-Naphthaleneacetic acid) is a synthetic analog of Auxin offering better solubility and stability.

2.1

Note

If required, depending on the nature of the negative control, prepare the same mixture without NAA to produce the control medium. Note that in flies expressing TIR1, a leaking degradation of the AIDtagged protein occures in the absence of auxin.

The composition of the degradation medium is 0.6% agar, 4% sucrose, 2.5mM

2.5*10^-3 Molarity (m) NAA, in water

2.2

Microwave until complete agar melting

2.3

Cool down to 70 °C

2.4

Pour 30mm plastic petri dishes (5ml of melted agar solution per dish)

2.5

Store in a plastic bag at 4°C protected from light

Note

The agar NAA medium is stable for two weeks when properly stored.

3

Triggering protein degradation in L3 larvae

3.1

Equilibrate NAA 30 mm dishes, and control dishes, prepared as described in section 2, to room temperature, and add a pinch of yeast granulates to the dishes

3.2

Using forceps, gently but quickly transfer up to 50 L3 larvae from tubes prepared as described in section 1 to a 30 mm dish containing NAA (same for control no NAA agar dish)

3.3

Quickly seal the dishes using a piece of parafilm Parafilm M Sigma Aldrich Catalog #P7793

to prevent the larvae from escaping

3.4

Puncture tiny holes (small enough so that larvae cannot pass through) in the parafilm membrane using a needle in order to ensure oxygen and CO2 exchange

3.5

Incubate the dishes at 25 °C the required amount of time

Note

Pronounced degradation is usually achieved within 30 minutes.

3.6

Remove the parafilm seal

3.7

Using forceps, gently collect the larvae from the agar dishes, and quickly proceed to desired operation, typically dissection of the imaginal discs.


Davide Gulotta

B Lubelli

I Rörig-Daalgard

A M Aguilar

M Askrabic

Kévin Beck

C Bläuer

A.M. D'altri V Cnudde

Hannelore Derluyn

RECOMMENDATION FOR THE DURABILITY ASSESSMENT OF POROUS BUILDING MATERIALS AGAINST SALT CRYSTALLIZATION

Keywords: Salt accelerated aging, sodium sulfate, sodium chloride, stone, brick

d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

EXTENDED ABSTRACT

Salt crystallization is among the most harmful deterioration mechanisms impacting the preservation of porous building materials worldwide. Therefore, predicting the materials' response to salt damage is crucial in the conservation practice and building sector to guarantee adequate performance and durability. These, in turn, are instrumental to achieving sustainable interventions. Numerical models have been developed to describe the salt decay susceptibility quantitatively, but the most diffused approach still relies on performing accelerated weathering tests in laboratory conditions.

So far, the main limitations associated with most of the available experimental and standard accelerated weathering tests arise from the generally long time they require, the lack of consensus on the methods for assessing the damage progression and extent, and the use of testing scenarios hardly representative of real-world conditions. These include simulating unrealistic accumulation and salt transport processes, which in turn significantly affect the resulting deterioration patterns and the final damage extent, and the use of remarkably high salt solution concentrations.

The RILEM Technical Committee (TC) 271-ASC, active between 2016 and 2022, pursued an innovative direction to simulate more realistic salt crystallization pathways to test single porous materials (stone and fired-clay brick units). The TC aimed to develop a reliable accelerated aging procedure for laboratories in the architectural heritage conservation and construction sectors. The requirements for the new procedure focused on achieving realistic results in a relatively limited time, without significantly altering the deterioration process and allowing for a simple damage assessment based on readily available and non-sophisticated techniques. The test simulates the deterioration effects induced by capillary transport of sodium sulfate and sodium chloride aqueous solutions, considered as single salts, toward the evaporative surface of cylindrical specimens.

Building on the experience of reinforced concrete durability research, the TC has explored the feasibility of a two-stage approach (Fig. 1) to trigger damage development and progression, only after a certain degree of pore filling -as a result of salt accumulation -is reached. The new procedure translates this theoretical assumption into two distinct testing phases: a preliminary salt accumulation phase, during which the porous substrate is contaminated with a salt solution with fixed concentration and capillary transport promotes its accumulation close to the evaporation surface without causing visible damage, followed by a propagation phase (Fig. 2). The propagation phase activates the damage development due to repeated crystallization and dissolution cycles. The testing conditions for the accumulation phase are the same for both salts. Specimens are subjected to capillary absorption of 5% and 10% concentrations (mass %) of sodium sulfate and sodium chloride solutions and then dried until the evaporation of at least 80% of the absorbed water.

The propagation phase follows, based on four 3-week cycles. Differently from the accumulation phase, the set conditions of such cycles differ (i.e., T and RH values, duration, and use of rewetting stages) depending on the type of salt employed. In brief, each single 3-week cycle of the propagation phase of NaCl employs a series of high relative humidity adsorption sub-cycles alternated with drying stages, followed by a rewetting step and a final drying (Fig. 3a). Each Na2SO4 propagation phase starts with a cooling and rewetting sub-cycle at room conditions, followed by drying (Fig. 3b). The rewetting steps for both salts are carried out with deionized water only. fired-clay bricks. The physical characteristics of such substrates cover an open porosity range between 13% and 50% (vol %) and a capillary water absorption interval between 50 and 1070 g/m 2 s 0.5 .

The new accelerated aging procedure has been recently published as a RILEM recommendation [START_REF] Lubelli | Recommendation of RILEM TC 271-ASC: New accelerated test procedure for the assessment of resistance of natural stone and fired-clay brick units against salt crystallization[END_REF]. The document details the two procedures for testing single porous materials and includes a simplified methodology based on visual observations, photographic documentation, and mass loss recording to guide the evaluation of the salt crystallization results. A damage glossary for identifying the deterioration patterns is also provided, derived from selected terms of the ICOMOS-ISCS Stone Deterioration Glossary [4] and the MDCS Damage Atlas [START_REF]MDCS Damage Atlas[END_REF].

  The new RILEM TC 271-ASC Recommendation for the Durability Assessment of Porous Building Materials Against Salt Crystallization SWBSS ASIA 2023 -Nara, Japan. September 20-22, 2023.

Figure 1 :

 1 Figure 1: Two-step damage development of stone/brick substrates due to salt crystallization (from [1])

Figure 2 :

 2 Figure 2: Photographic documentation of stone specimens (Tuffeau limestone) during the accumulation phase (a), after two propagation cycles (b), and at the end of the accelerated aging procedure (c).

  and RILEM TC 271-ASC members SWBSS ASIA 2023 -Nara, Japan. September 20-22, 2023.

Figure 3 :

 3 Figure 3: Testing conditions (propagation phase) characterizing each 3-week cycle of the NaCl (a) and Na2SO4 (b) testing procedure.Two round-robin testing programs have been conducted to validate the accelerated weathering procedure, involving ten research laboratories across Europe and the US[START_REF] Lubelli | A new accelerated salt weathering test by RILEM TC 271-ASC: preliminary round robin validation[END_REF]. The substrates tested during the validation phase include five stones (Lecce, Massangis and Migné limestone, Tuffeau, and Mšené "Prague" sandstone) and two

Getty Conservation Institute, Science Department, Los Angeles, US, dgulotta@getty.edu

www.rilem.net/groupe/271-asc-accelerated-laboratory-test-for-the-assessmentof-the-durability-of-materials-with-respect-to-salt-crystallization-355


A H Yahi

A Bouzidi

R Miloua

M Medles

A Nakrela

M Khadraoui

H Tabet-Derraz

R Desfeux

A Ferri

J-F Blach

The relationship between processing and structural, optical, electrical properties of spray pyrolysed SnO2 thin films prepared for different deposition times

Keywords: SnO2, thin films, spray pyrolysis, deposition time, structure, surface morphology, optical and electrical properties

SnO2 thin films were deposited on glass substrates at 350° C by spray pyrolysis technique for different deposition times (i.e. 4, 7, 10 and 13 min) from tin chloride (SnCl2, 2H2O). The X-ray diffraction analysis showed that all the synthesized films correspond to the tetragonal structure of SnO2. Depending on the deposition time, the estimated average crystallite size varied from 29 to 55 nm using Williamson-Hall analysis (36 to 65 nm using the Scherrer method). Atomic force microscopy analysis revealed homogenous surfaces with low values of roughness (9.9 to 27.7 nm). As measured by spectroscopic ellipsometry, the thickness of the films was ranging from 150 to 350 nm. The obtained SnO2 films displayed an average transmittance of 80 % and a direct optical band gap ranging from 3.98 to 4.09 eV. The Hall-effect measurements revealed that all the films are conductive with values of conductivity varying from 32.3 up to 127 Ω - 1 .cm -1 . From the obtained morphological, optical and electrical results, we conclude that spray pyrolysed tin oxide thin films are good candidates to be used in different fields, mainly in solar cell applications.

Introduction

Transparent conductive oxides (TCO) are well known for their applications in various fields, such as optoelectronic devices, especially in photovoltaic applications as transparent electrodes or antireflection films in solar cells, gas discharge display, flat screens, antifreeze windows, heat reflecting windows (buildings, ovens, ...), mirrors and electro-chromic windows, touch control screens and for electromagnetic protection The physico-chemical properties of these thin films are closely related to the processes and conditions of their growth. Indeed, it is possible to obtain films with an amorphous or crystalline structure according to the parameters used for their growth.

In the recently years, some researchers have examined the physical properties of SnO2 thin films prepared by spray pyrolysis technique. This researchers have studied the effect of solution flow, solution concentration, temperature and PH values on the properties of undoped SnO2 thin films [START_REF] Khelifi | Effect of solution flow on the properties of tin dioxide SnO2 thin films deposited by spray pyrolysis technique[END_REF][START_REF] Abdelkrim | Effect of solution concentration on the structural, optical and electrical properties of SnO2 thin films prepared by spray pyrolysis[END_REF][START_REF] Orimi | Optical characterization of SnO2 nanostructure thin films, annealed at different temperatures[END_REF][START_REF] Sukriti | Effect of pH values on the structural, optical and electrical Properties of SnO2 nanostructures[END_REF].

Khelifi et al. [START_REF] Khelifi | Effect of solution flow on the properties of tin dioxide SnO2 thin films deposited by spray pyrolysis technique[END_REF] obtained SnO2 nanocrystalline film for different flow rate. Abdelkrim et al. [START_REF] Abdelkrim | Effect of solution concentration on the structural, optical and electrical properties of SnO2 thin films prepared by spray pyrolysis[END_REF] also reported significantly reduced nanoparticules with increasing of solution concentration. Lotfi Orimi and Maghouli [START_REF] Orimi | Optical characterization of SnO2 nanostructure thin films, annealed at different temperatures[END_REF] prepared SnO2 thin films at 450 °C and then annealed at different temperatures, Sukriti and Chand [START_REF] Sukriti | Effect of pH values on the structural, optical and electrical Properties of SnO2 nanostructures[END_REF] have synthesized SnO2 nanostructures via precipitation method at different pH values.

Md sin et al. [START_REF] Md Sin | Effect of deposition time SnO2 thin film deposited using thermal CVD for humidity sensor application[END_REF] reported effect of deposition time on SnO2 thin film deposited using thermal CVD, Arini et al. [START_REF] Arini | The influence of deposition time and substrate temperature During the spray pyrolysis process on the resistivity and optical transmittance of 2 W% fluorine-doped tin oxide conducting glass[END_REF] reported the influence of deposition time during the spray pyrolysis process on the electrical resistivity and optical transmittance of 2 wt% Fluorine-doped tin oxide conducting glass.

To the best of our knowledge, the influence of deposition time on the properties of undoped SnO2 thin films using spray pyrolysis technique was not yet reported in the literature, the relationship between the film growth process and physico-chemical properties including surface morphology, optical and electrical properties is shown in this work.

The films are developed by spray pyrolysis technique which is widely used due to its simplicity and commercial visibility [16].

Experimental techniques

Spray pyrolysis-technique is used to prepare SnO2 thin films from tin chlorite (SnCl2, 2H2O).

2.63 g of this precursor is dissolved in 100 ml of distilled water and methanol using a few droplets of HCl to obtain a soluble solution of 0.1 mol.L -1 . Glass substrates are cleaned using ethanol, acetone and distilled water. Next, the SnO2 solution is sprayed onto the glass substrates at temperature of 350 ° C, and for different deposition time (i.e. 4, 7, 10 and 13 min).

The structural characterization is carried out at room temperature using a Bruker D2 PHASER X-Ray Diffractometer (XRD -CuKα radiation, λ = 1.5406 Å).

The surface morphology is analyzed by Atomic Force Microscopy (AFM) using a commercial microscope (Bruker, MultiMode) in ambient conditions.

The thickness of the films is investigated by Spectroscopic Ellipsometry (SE) at room temperature using a phase-modulated ellipsometer (UVISEL HR460 from Horiba Scientific) at wavelengths ranging from 300 to 1200 nm with 2 nm interval. An incidence angle of 70° is used for all measurements.

The optical transmittance is recorded from 200 nm to 2500 nm using UV-Vis-NIR JASCO type V-570 double beam spectrophotometer.

Finally, the electrical properties are obtained using ECOPIA HMS-5000 4 Hall Effect measurement at room temperature.

Results and discussion

Structural characterization

To investigate the crystalline quality of the films with various deposition times (4, 7, 10 and 13 min), XRD analysis was undertaken and measured patterns are shown in Fig. 1. All the peaks are indexed using ICDD card No. 041-1445 corresponding to the tetragonal phase of tin oxide SnO2. For all samples, the (1 1 0) peak is the most intense, while other peaks assigned as (2 0 0), (2 1 1) are also observed. The peaks (1 0 1), (2 2 0) and (3 0 1) appear at 10 and 13 min and the (3 1 0) peak appears only at 10 min.

The lattice constants a and c for tetragonal structure, are determined by the equation [START_REF] Chacko | Nanostructural and surface morphological evolution of chemically sprayed SnO2 thin films[END_REF]:

2 2 2 2 2 2 1 c l a k h d hkl +         + = (1)
where, 'dhkl' is the interplanar distance and h, k, l, are Miller indices.

The calculated and standard lattice constants are listed in The crystallite size of the films is calculated from the more intense peak (1 1 0) using the Scherrer formula [19]:

   cos .9 0 = G (2)
where, G is the crystallite size, β is the full width at half of the peak maximum (FWHM) in radians and 'θ' is the Bragg's angle. The crystallite size values are given in Table 1.

The calculated G value increases from 36 to 65 nm along with the increase of deposition time from 4 to 10 min and then slightly decreases from 65 to 54 nm for 13 min. We note that these values of G are higher than the ones found in the literature for films grown by the same technique; this would mean that the dislocation density is lower in our films [START_REF] Abdelkrim | Effect of solution concentration on the structural, optical and electrical properties of SnO2 thin films prepared by spray pyrolysis[END_REF][START_REF] Turgut | Synthesis and characterization of Mo doped SnO2 thin films with spray pyrolysis[END_REF][START_REF] Rahal | Effect of antimony doping on the structural, optical and electrical properties of SnO2 thin films prepared by spray ultrasonic[END_REF].

Md sin et al. [START_REF] Md Sin | Effect of deposition time SnO2 thin film deposited using thermal CVD for humidity sensor application[END_REF] obtained a relatively small crystallite size about 20 to 45 nm.

In addition a decrease in grain size up to 7 nm was observed following the increase of solution concentration, solution flow and PH values [START_REF] Khelifi | Effect of solution flow on the properties of tin dioxide SnO2 thin films deposited by spray pyrolysis technique[END_REF][START_REF] Abdelkrim | Effect of solution concentration on the structural, optical and electrical properties of SnO2 thin films prepared by spray pyrolysis[END_REF][START_REF] Sukriti | Effect of pH values on the structural, optical and electrical Properties of SnO2 nanostructures[END_REF].

The crystallite sizes were also determined using the Williamson-Hall method, by taking into account all of the peaks; the Williamson-Hall analysis also makes it possible to determine the

microstrain ε [21].
It can be written as:

     sin cos 4 + = G (3)
βcos(θ) is plotted with respect to sinθ for all films, where ε and G are calculated from the slope and y-intercept of the fitted line respectively as shown in Fig. 2.

The values of crystallite size determined by the Williamson-Hall method are close to the values obtained by the Scherrer formula as shown in Table 1.

We also observe a low microstrain (ε) for all the films grown at different deposition time, mainly at 10 minutes where ε is negligible (4.86×10 -6 ).

The orientation of the crystallites and the preferred directions of growth can also be deduced from the XRD patterns. It is quantified through the coefficient of texture of the (hkl) plane for all the peaks, the texture coefficient is given by [22]:

 = ) ( 1 ) ( 0 ) ( ) ( 0 ) ( ) ( hkl hkl hkl hkl hkl c I I N I I T ( 4
)
where I(hkl) is the measured intensity of X-ray reflection, I0 is the ICDD standard intensity and N is the number of reflections observed in the XRD pattern.

The calculated Tc values are presented in Table 2. The variation of the texture coefficient with deposition time for each peak has been depicted. In this study, Tc values of (2 0 0), (2 2 0) and

(3 1 0) peaks are relatively higher than those of other planes, which shows that there is no preferential orientation.

Surface morphology properties

Fig. 3 shows the AFM morphology of deposited SnO2 films at various deposition times. It can be seen that the films deposited during 4 and 7 min present a dense granular-like structure without cracks (Figs. 3a andb), whose grain diameter is ranging from 30 to 100 nm and 50 to 140 nm, respectively. The crystallinity of the films improves and the grain size becomes larger with the increasing of deposition time, suggesting that the particles in SnO2 films become smaller at low deposition time (4 and 7 min). At 10 min we observed a clear change in grain shape since pyramidal features are detected, as depicted in Fig. 3c (3D AFM image is presented in Fig. 3e to better evidence such pyramidal structure). In addition, the size of these surface morphological structures becomes very important, the average length being about 250 to 400 nm. Then, by increasing the time deposition until 13 min, a slight degradation for the surface morphology is observed, indeed the coexistence of both granular and pyramidal morphological structures is evidenced (see Fig. 3d). For this later sample, the average sizes of granular and pyramidal structures are about 50 nm and ranging from 200 up to 300 nm, respectively. Such a change in the grain shape was already found in previous works [11, [START_REF] Ajili | Spray solution flow rate effect on growth, optoelectronic characteristics and photoluminescence of SnO2: F thin films for photovoltaic application[END_REF][START_REF] Uysal | Structural and optical properties of SnO2 nano films by spincoating method[END_REF].

The evolution of the grain size measured by AFM as function of the deposition time follows exactly the same trend as the crystallite size determined by DRX (Scherrer formula and Williamson-Hall method) with a maximum size at t = 10 min as shown in Fig. 2.

The AFM root mean square roughness were found to be 9.9, 13.0, 27.7 and 22.1 nm, as determined on 10×10 µm² scan area for 4, 7, 10 and 13 min deposition time, respectively. These roughness values increase with the increase of the particle size, but they remain quite low for such deposited films, confirming their surface homogeneity. AFM topographies of SnO2 found by Abdelkrim et al and Tischner et al [START_REF] Abdelkrim | Effect of solution concentration on the structural, optical and electrical properties of SnO2 thin films prepared by spray pyrolysis[END_REF][START_REF] Tischner | Ultrathin SnO2 gas sensors fabricated by spray pyrolysis for the detection of humidity and carbon monoxide[END_REF] showd that the films present a uniform morphology but with small grain.

Optical properties

SE was used for the optical characterization of the thin films and mostly for the measurement of their thickness. These ellipsometric angles ∆ and Ψ are linked to the complex reflection coefficients R of polarized light (Rp and Rs for respectively a polarization parallel and perpendicular to the plane of incidence) by the following relation

 = = i S P e R R  

tan

. For each sample, the measured spectrum is analyzed using a model depending on the sample structure.

The unknown parameters (the thicknesses in our case) were determined by finding the global minimum of a merit function  2 (Levenberg-Marquardt algorithm) which compare the ellipsometric angles calculated by the model with the angles obtained in the measurements :

 =           -  +  -  =  n i i i th i th i 1 exp , 2 exp exp 2 exp 2 ) ( ) ( min ,    (5)
where n is the number of measured  and  pairs, exp ,i   and exp ,i   are the standard deviations of exp,i and exp,i. All fitting steps were performed using the Delta-Psi Horiba software (Horiba Scientific).

The optical functions of the substrate (glass slide) and the thin films of SnO2 were found in the database of the Delta-Psi Horiba software (Horiba Scientific).

The values of the coefficients for SnO2 comparing with literature [26] are showed in Table 3.

An exemple for the best fit of the optical proposed model comparing with the measured ellipsometric data of SnO2 deposited during 10 min is represented in Fig. 4, these optical functions were inserted in a three model layers for the modelling of ellipsometric spectra obtained on all samples: a semi-infinite glass layer substrate covered by a dense layer of SnO2, and a rough layer which can be represented as a SnO2 dense layer with holes filled by air; we used the Bruggeman [27] effective medium approximation for modeling this last layer.

The values of thicknesses were obtained after the modelling step and the results are presented in the Table 4. We can notice the monotonic increase of the film thickness with the deposition time.

Optical transmittance and reflectance spectra of SnO2 thin films are presented in Fig. 5. The average transmittance increases slightly with the increasing of deposition time and reaches around 80% in the visible region, many researchers who have developed SnO2 in the same conditions as our work, were found the same transmittance value [10-12]. The interference fringes which appear clearly in reflectance curves tighten for the film deposited during 13 minutes, this phenomenon can be explained by the increase in the thickness.

The optical band gap energy is obtained by the following relation [28]:

) ( ) ( g n E h A ah - =   (6)
where, hν is the photon energy and A, a constant, n = 2 for a direct allowed transition and n = 1/2 for an indirect allowed transition.

Eg values of band gap are determined by plotting (αhν) ² versus (hν) by intercept of the linear part of the plot with energy axis (Fig. 6).

The values of optical band gap of SnO2 thin films are varying from 3.98 to 4.09 eV. We can observe that the band gaps increase between 4 and 10 min and then decrease at greater deposition time, the measured optical band gap values was found by khelifi et al.

) exp( ) ( 0 u E h h     = (7)
where, α0 is the pre-exponential factor, hν the photon energy, and Eu is the band tail width or energy of disorder commonly called Urbach tail [29].

Eu can be estimated from the inverse slope of the linear plot between ln (α) and hν. The variation of band gap with Urbach tail is shown in Fig. 7.

The refractive index (n) reaches a maximum of 2.2 in the UV range than tends to 02 in the near infrared range and the refractive index (k) is correlated with α which is shown in Fig. 8.

It can also be noted that the reflectance is inversely proportional to the roughness which is shown in Fig. 9.

Table 4 summarizes the variation of band gap energy, crystallite size, roughness, thickness and Urbach tail for different deposition time. As can be concluded from XRD and AFM studies the crystallite size increases with increasing deposition time from 4 to 10 min. These results explain the low increase of the roughness with increase of deposition time which demonstrates the best quality of films obtained for 10 min despite the presence of roughness. However, the disorder is inversely proportional to the optical band gap, which explains the decrease of disorder as a function of deposition time.

Electrical properties

The electrical properties of thin films are dependent on various growth parameters such as composition, thickness, and substrate temperature [START_REF] Amroun | Investigation on the structural, optical and electrical properties of mixed SnS2-CDS thin films[END_REF].

The electrical properties of SnO2 films were investigated by Hall Effect measurements. The carrier concentrations, Hall coefficient, conductivity and sheet resistance of the films are given in Table 5. According to the obtained results, all samples have n-type conduction. The conductivity increases with the increase of deposition time from 32.3 Ω -1 .cm -1 at 4 min up to 127 Ω -1 .cm -1 at 10 min owing the surface condition, for a same condition at 0. In order to evaluate the efficiency of SnO2 thin films as transparent conducting oxides, we use the pareto front.

Conclusion

The aim of this work was to show that we can obtained a good properties of undoped SnO2 thin films in term of conductivity, transmittance, surface morphology and structural properties.

In the present study we tried to vary the deposition time to show the importance of processing and its influence on the physico-chemical properties of SnO2 thin films. The thin films (in the range 150-350 nm of thickness) were successfully deposited on glass substrate at 350 °C by spray pyrolysis technique. XRD study indicated that the films correspond to tin oxide with a tetragonal symmetry. The optical study showed high transmission and large optical band gap between 3.98 and 4.09 eV. From electrical measurements it was found that the films have ntype conduction. The films properties improve with the increase of the deposition time and thickness with a low degradation after 10 min. From these results, it can be concluded that the structural, morphological, optical and electrical properties strongly depend on the elaboration process of the deposited films and make them suitable candidates for optoelectronic devices and particularly in solar cells field.

[ 1 - 2 ].

 12 During the last years, SnO2 doped with fluorine or antimony, has been developed as an electrode in nano-crystalline dye-sensitized solar cells [3-4]. Tin oxide films may be prepared by various techniques such as sputtering [5], electron beam [6], sol-gel [7], chemical vapor deposition [8] and spin coating [9].

[ 10 ]

 10 is were in the range of 3.72-3.83 eV, byAbdelkrim et al. [11] is in the range of 3.84-4.09 eV and by,Sukriti and Chand [13] is in the range of 3.76 to 3.98 eV. We can well notice that the values of the optical band gap found by us is in agreement with the most part of the values found in the literature.The band gap is related to the appearance of band tails in material band diagram. This band tail states are responsible of the absorption in the low energies range. In this range the absorption coefficient is given by [29]:

  figure of merit) to different objectives. The difficulty is increased by the fact that even small numeric changes in weights can generate very different solutions. Such a situation is encountered in TCO optimal design [32].Fig. 10 shown a pareto front for SnO2 deposited at 04, 10, 07 and 13 min by spray pyrolysis and difference with literature which the values are showns in Table.6.

  6.

Fig. 1 .Fig. 2 .

 12 Fig. 1. XRD patterns of SnO2 thin films for different deposition times: a) 4 min, b) 7 min, c) 10 min and d) 13 min

Fig. 3 .Fig. 4 .Fig. 5 .Fig. 6 .Fig. 7 .Fig. 8 .Fig. 9 .

 3456789 Fig. 3. AFM topographic images of SnO2 films for deposition time of a) 4 min, b) 7 min, c) 10 min and d) 13 min. The scan area is 2 × 2 µm² for all the images. e) 3D representation of the surface morphology presented in c)

Fig. 10 .

 10 Fig. 10. A pareto front of SnO2 thin films prepared in this work and literature

Table 1 .

 1 The calculated a and c values

	are close to those given in ICDD card no: 41-1445 (a = b = 4.7382 Å, c = 3.1871 Å) and those
	from the literature, mainly when growth time is 10 min

[11, 18].

Table 1 .

 1 Values of lattice parameters of tetragonal SnO2, crystallite size G and microstrain ε

	t (min) a (Å)	c (Å)	Scherrer method		Williamson-Hall method (WH)
				(2Ɵ)	β	G	G (nm)	ε
				(°) FWHM (°) (nm)
	04	4.7107 3.2068 26.71	0.24	36	29	-1.02.10 -3
	07	4.7121 3.2008 26.71	0.19	47	42	+1.93.10 -4
	10	4.7426 3.1839 26.62	0.13	65	55	+4.86.10 -6
	13	4.7381 3.1792 26.67	0.16	54	46	-2.2810 -4

Table 3 .

 3 Coefficients of the optical function of SnO2

	The optical coefficient of	Values	Ref
	SnO2		values [27]
	n	1.776	1.923
		3.156	3.70
	s	3.995	3.738
	t	4.786 eV	3.386 eV
	0	1.236 eV	0.5064 eV

Table 4 .

 4 Structural, morphology and optical properties data of SnO2 films for various deposition times

	Deposition	Thickness	Eg	Roughness	Urbach tail	Grain size
	time	(nm)	(eV)	(nm)	(eV)	(nm)
	(mn)
	04	150	3.98	9.9	0.2894	29-36
	07	241	4.00	13	0.2853	42-47
	10	264	4.09	27.7	0.2453	55-65
	13	350	4.05	21.1	0.2693	46-54

Table 5 .

 5 Electrical properties of SnO2 thin films prepared by spray pyrolysis

	Deposition	Conductivity	Carrier Concentrations	Hall Coefficient	Sheet resistance
	time	(Ω -1 .cm -1 )	(cm -3 )	(cm 3 .C -1 )	Rsh(Ω.sq -1 )
	04 min	3.23 10 +1	-1.29 10 +20	-4.80 10 -2	2.05 10 +3
	07 min	5.87 10 +1	-1.69 10 +20	-3.67 10 -2	1.13 10 +3
	10 min	1.27 10 +2	-2.63 10 +20	-2.36 10 -2	4.50 10 +2
	13 min	7.30 10 +1	-1.21 10 +20	-5.12 10 -2	6.84 10 +2

Table 6 .

 6 Transmittance and sheet resistance of SnO2 thin films for our work and literature

			Our work					Refs
		04	07	10	13	[11]	[19]	[20]	[34]	[35]	[36]	[37]
		min	min	min	min
	T (%)	67.06 68.98 82.01 76.71 62.49	74.28	47.76	65	52	75.12	97
	400-900
	(nm)
	Rsh	2500	1130	450	684	401.8 109.81	138 1320 51.26 443.8 509
	(ohms/sq)

Acknowledgments

Chevreul Institute (FR 2638), Ministère de l'Enseignement Supérieur, de la Recherche et de l'Innovation, Hauts-de-France Region and FEDER are acknowledged for supporting and funding partially this work.


Nicolò Lo Presti

Antonio Maria D'altri

Luca Patruno

Giovanni Castellazzi

Tinhinane Chekai

Hannelore Derluyn

Stefano De Miranda

ON THE DEVELOPMENT OF A MICROMECHANICS-BASED RELATIONSHIP BETWEEN SALT CRYSTALLIZATION PRESSURE, PORE FILLING, AND DAMAGE IN POROUS BUILDING MATERIALS

Keywords: Pore pressure, Salt crystallization-induced damage, Pore Structure, Finite element analysis, Damage modelling

This contribution investigates the relationship between salt crystallization pressure, pore filling, and damage in porous building materials through a micromechanics-based approach. A 3D finite element (FE) model of a microscale representative volume element (RVE) of the porous material is developed, and several load scenarios are applied to the RVE to correlate salt crystallization pressure, pore filling, and damage in the RVE. The resulting relationships are then condensed into a computationally efficient off-line phenomenological model, calibrated on a large FE-based database, capable of predicting the macroscopic damage in the RVE due to any pseudo-time history of salt crystallization pressure and pore filling. The effectiveness of the phenomenological model is verified by comparing its results with the ones computed through the FE model, for load scenarios not included into the calibration dataset, achieving good agreement of results. Finally, the possibility of using this phenomenological model together with available multiphase models to predict moisture transport, salt crystallization pressure, and damage into porous building materials is discussed.

INTRODUCTION

Environmental actions, such as moisture transport and salt crystallization, are known to play a major role in the deterioration process of porous building materials [START_REF] Lubelli | Towards a more effective and reliable salt crystallization test for porous building materials: state of the art[END_REF]. Although significant efforts have devoted to the development of experimental procedures for the assessment of resistance of porous building materials against salt crystallization [START_REF] Lubelli | Recommendation of RILEM TC 271-ASC: New accelerated test procedure for the assessment of resistance of natural stone and firedclay brick units against salt crystallization[END_REF], the development of reliable numerical tools to predict salt weathering is still challenging.

In this contribution, the possibility to derive a micromechanics-based relationship between salt crystallization pressure, pore filling, and damage in porous building materials is investigated and discussed.

Firstly, a 3D finite element (FE) model of a microscale representative volume element (RVE) of the porous material [START_REF] Grementieri | A multi-scale approach for the analysis of the mechanical effects of salt crystallisation in porous media[END_REF] is developed. The RVE geometry is based on a simplified pore structure with statistically representative properties in agreement with experimental data [START_REF] Castellazzi | A coupled multiphase model for hygrothermal analysis of masonry structures and prediction of stress induced by salt crystallization[END_REF]. Secondly, several load scenarios in terms of salt crystallization pressure and pore filling are applied to the RVE, through various pseudo-time histories, and the macroscopic damage is directly measured on the RVE. Accordingly, relationships between salt crystallization pressure, pore filling, and overall damage in the RVE are obtained (Section 2). Such micromechanics-based relationships are then condensed into a computationally efficient offline phenomenological model, calibrated on a large FE-based database, able to predict the damage in the RVE due to any pseudo-time history of salt crystallization pressure and pore filling. The effectiveness of the phenomenological model is thus checked by comparing its results with the ones computed through the FE model, for load scenarios not included into the calibration dataset (Section 3).

The possibility to use this phenomenological model together with available multiphase models [START_REF] D'altri | Towards a more effective and reliable salt crystallisation test for porous building materials: Predictive modelling of sodium chloride salt distribution[END_REF][START_REF] Castellazzi | A staggered multiphysics framework for salt crystallization-induced damage in porous building materials[END_REF] to predict moisture transport, salt crystallization, pressure and damage into porous building materials is finally discussed (Section 4).

FINITE ELEMENT MODEL

A solid FE model of the RVE is generated by considering the actual porosity and the mean pore radius of the material. A nonlinear plastic-damage constitutive law is adopted for the material matrix, by assuming homogenized mechanical properties. Several load scenarios are applied to the RVE with varying salt crystallization pressure and pore filling pseudo-time histories. After de-loading the pore pressure, the macroscopic damage D is directly measured on the actual condition of the RVE. According to this, relationships between salt crystallization pressure, pore filling, and macroscopic damage are obtained (Figure 1). In particular, Figure 1 shows an example of macroscopic damage Dpressure relationship for constant pore filling (in particular, the saturation degree of crystallized salt, , is set equal to 1), as well as an example of damaged RVE.

Nicolò Lo Presti, Antonio

PHENOMENOLOGICAL MODEL

The aforementioned relationships are subsequently condensed into an offline phenomenological model that is computationally efficient. Such model is calibrated using a large database of FE simulations. To verify the efficacy of the phenomenological model, its outcomes in terms of predicted macroscopic damage D* are compared against those obtained by the FE model (in terms of macroscopic damage D) for load scenarios that were not part of the calibration dataset, as shown in Figure 2. On the development of a micromechanics-based relationship between salt crystallization pressure, pore filling, and damage in porous building materials

MULTIPHYSICS SIMULATIONS

Such phenomenological model is finally coupled with existing multiphase models [START_REF] Castellazzi | A coupled multiphase model for hygrothermal analysis of masonry structures and prediction of stress induced by salt crystallization[END_REF][START_REF] D'altri | Towards a more effective and reliable salt crystallisation test for porous building materials: Predictive modelling of sodium chloride salt distribution[END_REF] to predict moisture transport, salt crystallization, pressure and damage into porous building materials through multiphysics simulations. An example of application is shown in Figure 3, where the drying of a porous building material initially saturated with saline solution and an evaporating top surface is shown in terms of pore filling (left) and macroscopic damage D* (right) contour plots.

CONCLUSIONS

In conclusion, this study explored the possibility to develop relationships between salt crystallization pressure, pore filling, and damage in porous building materials using a micromechanics-based approach. In this context, a phenomenological model based on micro-FE outcomes has been employed together with existing multiphase models to conduct multiphysics simulations to account for salt crystallization-induced damage into porous building materials.

  Maria D'Altri, Luca Patruno, Giovanni Castellazzi, Tinhinane Chekai, Hannelore Derluyn, and Stefano de Miranda SWBSS ASIA 2023 -Nara, Japan. September 20-22, 2023.

Figure 1 :

 1 Figure 1: Example of macroscopic damage Dpressure curve for constant pore filling ( =1), left, and example of damaged RVE, right.

Figure 2 :

 2 Figure 2: A posteriori comparison between FE and phenomenological models. Top left: adopted pseudo-time history of the pore pressure. Bottom left: adopted pseudo-time history of the pore filling. Right: comparison of the evolution of macroscopic damage between FE (D) and phenomenological (D*) models.

Figure 3 :

 3 Figure 3: Example of multiphysics simulation of a drying phase: pore filling (left) and macroscopic damage D* (right) contour plots.

ACKNOWLEDGEMENTS

The support from the European project CRYSTINART through the Joint Programming Initiative on Cultural Heritage (JPI-CH) is gratefully acknowledged. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 101029792. H. Derluyn acknowledges the support from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 850853)".