Vivien Dubois
email: vivien.dubois@inrae.fr

Eva Falipou

Claire Lauvernet

Catherine Boutin

Wastewater data from individual homes: Quantitative and qualitative measurements

Keywords:

a b s t r a c t

The data article is related to the generation of raw wastewater from 15 single-family dwellings. Such a dataset is rare. They are complicated to set up due to the technical difficulty of deriving a representative sample of this kind of pollution, composed of suspended solids potentially very coarse in size, compounded by the administrative difficulty of performing these measurements on private property. The data were obtained by means of two distinct and complementary monitoring campaigns: i) continuous measurement of the volumes discharged by three of the 15 dwellings during more than one year, and ii) characterization, in terms of both quality and quantity, of more than 300 raw wastewater samples discharged over 24 consecutive hours by all 15 houses during weekly periods of seven consecutive days, which deliberately included weekend days. Their acquisition methodologies are described. The validation's methodologies, also described, include a R script. The data analysis can be used for i) designing and operating onsite and small wastewater treatment systems and ii) characterising the strictly domestic pollution. Therefore, this data article is associated with the manuscript "Quantification and qualification of the urban domestic pollution discharged per households and per resident".The hydraulic values obtained with continuous measurement are available in two units: in l.s -1 as primary data and in l.h -1 as secondary data. They can be reused at any time step. These elements could be incorporated into future research or innovations related to single-family dwellings. In a general point of view, such data could be introduced in databases used for Life Cycle Assessment. These values can also be used in sanitation (collection, design and operation) and be useful to better specify the potential for the recovery of domestic wastewater.

© 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

Specifications Table

Subject

Water Science and Technology Specific subject area Wastewater treatment and sanitation Type of data

Raw wastewater quantity and quality data (campaign ii) :

Method 1: collection of all the raw wastewater discharged from the house for 24 hours within a 1,0 0 0-liter graduated tank fed by a pumping station and placed in a shaded spot.

Value of the Data

• These data are useful as they characterize simultaneously the volumes and concentrations of raw wastewater discharged by households with a known number of residents. • This dataset is rare due to both the technical difficulty involved in conducting a sampling program representative of actual pollution and the administrative difficulty of performing these measurements on private property. • The sanitation community can directly benefit from these data.

• The data can be used to design onsite and small wastewater treatment systems.

• These data may be used for characterising the strictly domestic pollution.

• The dataset could be useful in further research on the recovery of domestic wastewater.

• The dataset could also enrich the databases used for Life Cycle Assessment.

Data Description

The dataset given in the supplementary data corresponds to: i) three series of hourly volumes measured for at least 21 months and ii) 302 daily quantitative and qualitative characterizations of raw wastewater, sampled so as to represent the discharge over 24 consecutive hours. The three houses H 1 , H 10 and H 11 underwent two monitoring campaigns i) and ii), while the other 12 houses, i.e. H 2 to H 9 and H 12 to H 15 , were solely involved in campaign ii).

The composition of the resident families was known and varied across households, from a single person to families composed of several adults (2 or 3), along with a variable number of children, from none to four. The maximum number of residents in any single house was six. The residents' ages were not known with any precision; only the distinction between adult and child, based simply on age recorded as younger or older than 18, was made. The 15 houses were sorted by increasing number of adult residents, then within each adult number category by increasing number of children residents, thus leading to the numbering system chosen for these 15 houses. The term "resident" refers to any individual who typically occupies, as a primary place of residence, the dwelling unit. Hence, a child attending boarding school during the week is a "resident" despite not being systematically present when pollution measurements are performed. Conversely, guests staying at the unit are not counted as "residents" even though the additional on-site activity generated by their stay and/or presence may be included in measurements.

All the parameters of the different households are summarised in the Table 1 below: The dwelling selection criteria are not extremely stringent; the dwelling selection was based primarily on technical feasibility criteria relative to the requisite monitoring in private space.

The data file contains, under the "Comments" tab: the locations of the 15 houses, the number of adults and children residents, the data acquisition methodologies for the two distinct but complementary monitoring campaigns, as well as the chemical analysis methods. For the continuous monitoring of raw wastewater volumes (campaign i), the pumping station surface areas are also given in the "Comments" file. The precise measurement dates and validated hourly flow rates are presented in three "Volumes" files individualized by houses H1, H10 and H11. For campaign ii), the "Raw wastewater characterization" file lists: house references, precise measurement dates, values of the validated measurement concentrations, and daily volumes.

24h composite samples (campaign ii) were acquired during weekly periods of seven consecutive days, which deliberately included weekend days. These sampling campaigns were conducted between one and five times, thereby covering several seasons. The Table 1 shows the number of weekly monitoring and the number of 24h composite samples available.

For the continuous monitoring of raw wastewater volumes (campaign i), the acquisition periods, began in November 2013 for the two sites H1 and H10 and later, in February 2015, for H11. Lasting at least 23 months, the durations are ranging from 1 year, 8 months to 2 years, 2 months depending on the dwelling and T the periods of missing data, resulting from technical issues (e.g. empty batteries, defective water height recorder devices). The number of continuous daily monitoring are 611 d, 533 d and 432 d respectively for dwellings H1, H10 and H11.

The water heights data recorded during the continuous monitoring are deposited in the Data INRAE repository as primary data (see [START_REF] Dubois | Continuous measurement of the volumes discharged from three French single-family homes[END_REF] ).

The volumes data may be processed with respect to various time steps, i.e. day, week, month, season and year. For example, it is possible to generate the average daily hydrographs of produced raw wastewater, by hourly interval, and in so doing reflect the household activity taking place inside the dwelling. Fig. 1 , based on 25,584 data points, displays the hydrograph of house H10, at a daily scale, in the form of 24 box plots representing the median, 1st and 3rd quartiles, and upper bound. The left panel of the figure has been produced with the validated complete dataset, while the right panel was generated using a dataset that excluded all statistically outlying values (i.e. beyond the upper bound), thus reducing the number of data points by 9 %. This result does in fact correspond to a close-up image of the left part of the graph with respect to amplitude: [0 -100 L.h-1]. Fig. 2 shows the specific consumption each day of the week, as visualized using the seven average daily hydrographs for the seven days of the week. Wastewater composition data are numerous, and the ratios calculated between the various chemical forms serve to confirm the strictly domestic nature of the wastewater to be treated. An example presented in Fig. 4 refers to the 100 TP/COD ratio. Since phosphorus mainly originates from human activity alone, or from washing, this ratio may be used to trace a given daily household activity. Fig. 4 indicates the average of the 1 to 5 values of the 100 TP/COD ratio available by day of the week as well as by house. This evaluation applies to the 13 households able to provide the seven daily data points that enable comparison at the weekly scale. Table 2 .

Experimental Design, Materials and Methods

For a better understanding you can refer to Table 1 .

Continuous monitoring of raw wastewater volumes (campaign i)

Quantitative monitoring was performed by means of load flow measurements:

• a piezometer-type pressure sensor measured the water height at a pumping station, controlled by float switches. • the pressure sensor was connected to a data acquisition unit that recorded water height values at a given frequency.

The pump station was cylindrical in shape. Its effective surface area, which remained constant, was measured by calculating the ratio between the volume discharged by the pump during emptying and the height variation induced by this emptying step. These water heights were recorded every minute (see [START_REF] Dubois | Continuous measurement of the volumes discharged from three French single-family homes[END_REF] ) and multiplied by the calculated unit surface area to get the flow rates in volume per minute.

The probe detected amplitude variations of at least 1 mm. The validation step detects which small amplitude of water corresponds to either the raw wastewater contribution or the emptying sequences. These were episodes of slight turbulence at the surface water potentially caused by falling condensation droplets. As such, all deviations with an absolute value of 1 mm were retained, provided that they were the direct consequence of other deviations equal to or greater than 1 mm. The other deviations, grouped with the zero deviations, were systematically deleted. A script written in R language computing this data processing is available in a specific supplementary material. Based on validated water height values, it was possible to calculate the flow rates for each hour defined in the GMT + 1 time zone during winter and in GMT + 2 during summer (see [START_REF] Dubois | Quantification and qualification of the urban domestic pollution discharged per household and per resident[END_REF] ).

Characterization, in terms of both quantity and quality, of the raw wastewater (campaign ii)

The data were collected from September 2010 to March 2012 for five houses (H5, H7, H13, H14 and H15) and from September 2013 to February 2017 for the ten others (H1, H2, H3, H4, H6, H8, H9, H10, H11, H12). Samples were performed during weekly periods of seven consecutive days, which deliberately included weekend days. Depending on the particular situation, these sampling campaigns were conducted between one and five times, thereby covering several seasons.

The data were recorded according to two distinct modes.

• Method 1

• collecting all the raw wastewater discharged from the house for 24 hours within a 1,0 0 0liters graduated tank, fed by a pumping station and placed in a shaded spot • homogenizing the volume collected using a drum pump (B2 Vario Niro, manufactured by Lutz) • pumping a portion of the wastewater to a bucket

• homogenizing the portion of wastewater • bottling for laboratory analysis • emptying, rinsing with clean water and draining the graduated tank before being placed back into use.

The daily volume was determined by reading the water level in the storage tank, which had previously been marked for every 50-liter increment.

• Method 2: flow-sensitive sampling • maintaining submerged the extraction hose in the pipe connected to the wastewater treatment plant. The end of this extraction hose is not fitted with a screen • emptying the pipe of old wastewater during 15 seconds after starting the pump.

• simultaneously, homogenizing the volume of the lift station • then starting the wastewater sampling at each pump activation stroke by virtue of a water sensor-presence detector that triggered a response from the refrigerated automatic sampler. The end of the extraction hose, not fitted with a screen, was submerged in the pipe connected to the wastewater treatment plant

The daily volume was collected using two different procedures. The first one (method 2a) consists in multiplying the number of pump strokes by the average volume pumped. The other method (method 2b) is based on actual knowledge of the pumped volumes.

Both methods have been used here. Since the raw wastewaters are extremely fresh and contain much solid matter, the storage of all wastewater produced during a given day was preferred, namely as a means of guaranteeing that all suspended solids would be taken into account. Denied the possibility of installing and feeding the two storage tanks and provided the presence of a pumping station, method 2 was selected. Accordingly, method 1 was adopted for seven households (H1, H5, H7, H10, H12, H13 and H14) and Method 2 for the eight others (H2, H3, H4, H6, H8, H9, H11 and H15). This chosen method is mentioned in the data set.

The parameters analysed are COD, BOD5, SS (Carbon parameters), KN, NH4 + -N and TP (Nutrients parameters) (see [START_REF] Dubois | Quantification and qualification of the urban domestic pollution discharged per household and per resident[END_REF] ). The physicochemical analyses were carried out within Cofrac-certified laboratories or facilities with equivalent credentials, in strictly respecting the mandated analysis timeline. The different analytical standards used by each analytical laboratory and for each parameter are given in the supplementary material.

The method for validating the physicochemical data required the following:

• the strict adherence to sample storage conditions and analysis time. Sixteen samples from house H9 collected at the end of the week were kept in the freezer. A column in the «Raw wastewater characterization » line in the supplementary material indicates this conservation mode. • a comparison of the concentrations of nitrogen forms: verification that the NH4 + -N concentrations were indeed less than the KN concentrations. Otherwise, the set of parameters corresponding to this sampling was excluded from the dataset.

Fig. 1 .

 1 Fig. 1. Average daily hydrographs (volume in L / hourly interval) covering the entire data acquisition period of house H 10 : with the validated complete dataset (left), after removal of the statistically outlying values (right).

Fig. 2 .

 2 Fig. 2. Average daily hydrographs of raw wastewater, covering the entire data acquisition period, by day of week for house H 10 .

Fig. 3

 3 Fig. 3 schematically depicts the two distinct modes of data acquisition used for the characterization of the raw wastewater.Wastewater composition data are numerous, and the ratios calculated between the various chemical forms serve to confirm the strictly domestic nature of the wastewater to be treated. An example presented in Fig.4refers to the 100 TP/COD ratio. Since phosphorus mainly originates from human activity alone, or from washing, this ratio may be used to trace a given daily household activity. Fig.4indicates the average of the 1 to 5 values of the 100 TP/COD ratio available by day of the week as well as by house. This evaluation applies to the 13 households able to provide the seven daily data points that enable comparison at the weekly scale. Table2.

Fig. 3 .

 3 Fig. 3. Schematic diagram of the data acquisition methods for characterizing raw wastewater.

Fig. 4 .

 4 Fig. 4. Weekly trend in the average daily 100 TP / COD ratios of the effluent from 13 households.

these parameters were dependent on each laboratory and have been listed in supplementary material .

			triggered a
		response from the refrigerated automatic sampler. Daily volume acquired
		according to two distinct protocols: a) by multiplying the number of pump
		strokes by the average pumped volume ( Method 2a ) and b) actual knowledge
		of the pumped volumes ( Method 2b ).
		Parameters analysed: COD, BOD 5 , SS, KN, NH 4	+ -N and TP. The standards
	implemented to analyse Data format Raw, filtered, analysed
	Description of data collection	The dwelling selection criteria are as follows:
		• serving as a main residence,
		• being used solely for household activities(without any connection to the
		farming or agrofood processing sector,
		• featuring a conventional plumbing installation, devoid of any dry toilets or
		use of recycled water inside.
		These selection criteria are not stringent. The dwelling selection was based
		primarily on technical feasibility criteria relative to the requisite monitoring in
		private space.
	Data source location	The 15 houses are distributed throughout the French national territory:
		campaign i):
		• H 1 in the Rhône department (69)
		• H 10 in the Saône-et-Loire department (71)
		• H 11 in the Drôme department (26)
		campaign ii):
		• H 1 in the Rhône department (69)
		• H 2 , H 3 , H 4 , H 6 and H 8 in the Côtes-d'Armor department (22)
		• H 5 , H 7 , H 13 , H 14 and H 15 in the Tarn department (81)
		• H 9 in the Meuse department (55)
		• H 10 in the Saône-et-Loire department (71)
		• H 11 in the Drôme department (26)
		• H 12 in the Eure-et-Loir department (28)

Homogenization using a drum pump (B2 Vario Niro, manufactured by Lutz). Sampling for physicochemical analysis. Daily volume determined by reading the water level in the storage tank. Method 2: sampling of the wastewater in sync with its rate of inflow, downstream of the existing pumping station. Sampling upon each pump activation stroke by virtue of a water sensor-presence detector that ( continued on next page ) Data accessibility The data of the campaign i) and ii) have been deposited to Data INRAE. The open source format is .csv file or zip form. Repository name: Continuous measurement of the volumes discharged from three French single-family homes Data identification number: doi: 10.15454/HMTSXZ Direct URL to data: https://doi.org/10.15454/HMTSXZ Related research article V. Dubois, E. Falipou, C. Boutin, Quantification and qualification of the urban domestic pollution discharged per household and per resident (2022) , Water Science and Technology, 85 (5) 1484-1499. https://doi.org/10.2166/wst.2022.064 .

Table 1

 1 Parameters of the different households.

			Number of resident		24 h composite sample
					Campaign i)	Campaign ii) (2a: number of pump
	Households French department	Adults	Children	(storage tank)	stroke, 2b: pumped volume)
	H1	69 (Rhône)	1	0	1
	H2	22 (Côtes-d'Armor)	2	0		2a
	H3	22 (Côtes-d'Armor)	2	0		2a
	H4	22 (Côtes-d'Armor)	2	0		2a
	H5	81 (Tarn)	2	0	1
	H6	22 (Côtes-d'Armor)	2	1		2a
	H7	81 (Tarn)	2	1	1
	H8	22 (Côtes-d'Armor)	2	2		2a
	H9	55 (Meuse)	2	2		2a
	H10	71 (Saône-et-Loire)	2	3	1
	H11	26 (Drôme)	2	4		2a
	H12	28 (Eure-et-Loir)	2	4		2b
	H13	81 (Tarn)	3	1	1
	H14	81 (Tarn)	3	1	1
	H15	81 (Tarn)	3	2	1

Table 2

 2 Campaign ii) monitoring conducted in each house. House H 1 H 2 H 3 H 4 H 5 H 6 H 7 H 8 H 9 H 10 H 11 H 12 H 13 H 14 H 15

	Number of weekly monitorings	5	2	3	3	2	4	2	2	5	4	5	5	4	1	2
	Number of 24h composite samples available 34 10 17 18 14 26 14 8	35 25 30 29 21 7	14

Acknowledgments

The data collated here were collected by INRAE and furnished by three entities: the Côtes d'Armor Departmental Council, the Paris Region Directorate of the CEREMA Research Center, and the firm Premier Tech Eau et Environnement. The authors would also like to warmly thank Gaëlle Le Quellenec and Philippe Branchu for their personal commitment to the program coordinated by INRAE. Our gratitude is also extended to Roger Lacasse for sharing data initially collected as part of a program led by the Veolia company (Christian Vignoles) and set up as a consortium among several firms, including Premier Tech Eau et Environnement.

The authors sincerely thank the French Office for Biodiversity for its financial support.

Data Availability

Continuous measurement of the volumes discharged from three French single-family homes (Original data) (Dataverse).

Ethics Statements

Informed consent of all participants has been obtained.

CRediT Authors Statement

Vivien

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.


G Celeste

V Guipont

D Missoum-Benziane

G Kermouche

S Sao-Joao

S Girard- Insardi

D Chatelain

Assessment of agglomerated ceramic powders under impact by cold spraying

Most of ductile metals can be deposited by cold spray (CS). For brittle ceramic, such solid-state deposition process is still questionable, but some recent work on Ti02 or hydroxyapatite powders have shown that micrometric ceramic powder could be deposited by CS. In this work, it is claimed that the nature and the porous architecture of a ceramic powder with agglomerated ultra-fine grains play an important role on the impact behaviour. The aim of this work is to investigate the deformation behaviour of ceramic agglomerated powders under high velocity impact. Two different powders, respectively 3YSZ and Y2O3, were selected in order to study their architectures (particle size, porosity, density, crystallite size, etc.). Cold spray "splats" experiments, with various spraying distances to vary the particles velocities upon impact, were carried out to observe the deformation and fragmentation. In case of Y2O3, cold spray with dynamic vacuum surrounding atmosphere up to 3kPa were also prepared to evaluate the role of the atmosphere on the resulting impact. In parallel, in situ SEM micro-compression tests at 10 -2 s -1 on cross-sectioned 3YSZ particles involving flat-punch nano-indentation and micropillar compression were performed. By modelling the compression tests, the aim is to identify a Drücker-Prager behaviour law suitable for an agglomerated ceramic powder under quasi-static compression. Such deformation behaviour could help to better understand the compaction behaviour of agglomerated powders.

1.

Introduction

Cold Spray (CS) is a solid-state deposition process based on severe plastic deformation of powders. It is well established that ductile metallic materials can be processed by cold spray for coating solutions, repairing or manufacturing applications [START_REF] Papyrin | Cold spray technology[END_REF], [START_REF] Li | Solid-state additive manufacturing and repairing by cold spraying: A review[END_REF] With such spraying process, rather fine powders (20-50 μm) are accelerated by a supersonic gas stream at a temperature lower than the melting temperature of the material. Therefore, heatinduced oxidation and phase transformation, thermal stress, and other common problems encountered in thermal spray processes are very limited. Dense coatings involving several pure metals and alloys can be obtained by CS. As-sprayed or heat-treated coatings can exhibit high level mechanical or electrical properties [START_REF] Moridi | Cold spray coating: review of material systems and future perspectives[END_REF], [START_REF] Assadi | Cold spraying -A materials perspective[END_REF].

For brittle ceramics, such "cold" deposition process is still questionable, but it was found that rather thick and adhesive coatings could be obtained with specific ceramic powders deposited on metallic, ceramic, or polymeric substrates: e.g., hydroxyapatite (HA) [START_REF] Kergourlay | First Cold Spraying of Carbonated Biomimetic Nanocrystalline Apatite on Ti6Al4V: Physical-Chemical, Microstructural, and Preliminary Mechanical Characterizations: First Cold Spraying of Carbonated Biomimetic Nanocrystalline[END_REF]- [START_REF] Vilardell | Functionalized coatings by cold spray: An in vitro study of micro-and nanocrystalline hydroxyapatite compared to porous titanium[END_REF], TiO2 [START_REF] Yang | Low temperature deposition and characterization of TiO2 photocatalytic film through cold spray[END_REF]- [START_REF] Kliemann | Formation of Cold-Sprayed Ceramic Titanium Dioxide Layers on Metal Surfaces[END_REF] Y203 [START_REF] Kong | Fabrication Of Y2O3 Coatings By Cold-Spray[END_REF] or SiC [START_REF] Seo | SiO2 and MoSi2 formation on Inconel 625 surface via SiC coating deposited by cold spray[END_REF]. Dense ceramic powder is not relevant because the breaking of the particles leads to blocky fragments embedded like grit residues in a sand blasted surface. Recent works on pure ceramics by CS are mainly devoted to ceramic powders in the form of agglomerates that could be more suitable for cold spray deposition. On a fine scale, the nature and size of the crystallites may allow for rearrangements of the material, or even micro-plasticity under the effect of the high energy impact. The impact behaviour of agglomerated powders that can adhere with compaction of the porous particles has been evidenced in case of HA or TiO2 when powders are exhibiting nano-sized grains [START_REF] Yamada | Fabrication of Titanium Dioxide Photocatalyst Coatings by Cold Spray[END_REF], [START_REF] Vilardell | Dense nanostructured calcium phosphate coating on titanium by cold spray[END_REF]. Therefore, the synthesis route can play a role like for TiO2 anatase powder involving hydrothermal process [START_REF] Salim | The Synthesis of Titanium Dioxide (TiO 2 ) Powder for Cold Spray Process[END_REF]. Moreover, powder post-treatment like calcination of TiO2 can have a significant role on the resulting coating build up [START_REF] Rahim | Effect of Powder Calcination on the Cold Spray Titanium Dioxide Coating[END_REF]. The nature and the surface morphology of the substrate could also influence drastically the impact behaviour and the mechanical anchoring of the ceramic powder [START_REF] Vilardell | Feasibility of using low pressure cold gas spray for the spraying of thick ceramic hydroxyapatite coatings[END_REF].

For a similar solid-state kinetic spraying of ceramics, known as Aerosol Deposition (AD) process, Akedo et al. introduced the concept of Room Temperature Impact Consolidation (RTIC) [START_REF] Akedo | Room Temperature Impact Consolidation (RTIC) of Fine Ceramic Powder by Aerosol Deposition Method and Applications to Microdevices[END_REF] and Park et al. suggested a shockinduced plasticity and fragmentation phenomena [START_REF] Park | Shock-induced plasticity and fragmentation phenomena during alumina deposition in the vacuum kinetic spraying process[END_REF]. In AD, the impact behaviour concerns isolated ultra-fine particles powders previously dispersed in a pressurized gas and further accelerated in a vacuum chamber though a supersonic nozzle. Particles of sufficient size (200nm -5μm) undergo the RTIC mechanism on impact by fracturing and plastic deformation and therefore adhere to the substrate. [START_REF] Moos | An Overview of the Aerosol Deposition Method: Process Fundamentals and New Trends in Materials Applications[END_REF]. Films and coatings of different natures of ceramics were created: Al2O3 [START_REF] Exner | Powder requirements for aerosol deposition of alumina films[END_REF], HA [START_REF] Hahn | Preparation and in vitro characterization of aerosol-deposited hydroxyapatite coatings with different surface roughnesses[END_REF], TiO2 [START_REF] Fan | Characterization of Microstructure of Nano-TiO2 Coating Deposited by Vacuum Cold Spraying[END_REF], YSZ [START_REF] Mishra | Influence of Process Parameters on the Aerosol Deposition (AD) of Yttria-Stabilized Zirconia Particles[END_REF] or Y2O3 [START_REF] Ashizawa | Investigation of fluoride layer of yttria coatings prepared by aerosol deposition method[END_REF]. For the cold spray of ceramics, the challenge might be to promote the high-velocity impact of such ultra-fine or nano-sized particles when agglomerated in micrometric granules. In addition, it is claimed that the role of the porous architecture of agglomerated particles involving nano-sized and micro-sized features shall have a predominant role on the impact behaviour and the deposition process itself.

The present work aims at exploring the CS of various agglomerated ceramic powders to investigate the role of the nature of the material and those of the architecture of the particles. The purpose is to assess different ceramic materials that could vary with intrinsic toughness and hardness and particles features in the nano-size range (crystallites size, porosity, and internal cohesion). Al2O3, ZrO2 and Y2O3 oxide ceramics has been selected because a solid-state deposition process might be of great interested to prevent effects like allotropic, eutectic, amorphous transformations or thermal decomposition that always occur when thermally sprayed. It could also open new processing routes for functional ceramic coatings that could be doped with thermo-sensitive species.

In this work, two nanostructured ceramic feedstock powders: 3YSZ medium, as atomized and Y2O3 medium, as atomized from NANOE were prepared by wet method followed by spray drying. The characteristics of each powder were investigated by SEM and physical methods (BET, …) and further "splat" experiments were implemented involving Low Pressure Cold Spray (LPCS) in atmospheric pressure or under dynamic vacuum. The aim is to evaluate the deformation behaviour of individual particles after a dynamic impact in order to address experimentally the mechanisms involved. In parallel, flat punch nano-indentation and micropillar compression experiments were implemented on single 3YSZ particles in order to monitor the mechanical behaviour under micro-compression. By modelling the micro-compression tests, a Drücker-Prager behaviour law suitable for soil materials shall be fitted for agglomerated ceramic according to experimental data of micro-mechanical tests. Future work will focus on this deformation behaviour to be integrated into a numerical particle impact model for comparison with the experimental results of the cold spray.

Materials and methods

Ceramic feedstock powders: Two types of agglomerated powders, respectively 3 mol% Yttria Stabilized Zirconia (3YSZ) and cubic Yttria (Y2O3), were produced with precursors obtained by wet chemical precipitation (Nanoé, Ballainvilliers, France). After drying, precipitates are dispersed in a liquid suspension. Subsequent atomization of the suspensions was carried out by spray drying. One batch of each atomized ceramic powders, respectively 3YSZ and Y2O3 were further prepared by sieving to enable particles diameters ranging between 30-40μm.

Spaying experiments: Aluminium alloy A2017 substrates with 30mm×30mm×3mm dimensions were prepared with one polished surface up to 1µm with a diamond solution and then cleaned with ultrasound. Spraying experiments were carried out using a Low-Pressure Cold Spray facility (LPCS) allowing air or nitrogen gas up to 600°C/0.6MPa (D523, Dycomet Europe, The Netherlands). LPCS system has a radial injection of the powder in the downstream part of the convergent/divergent nozzle. The cold spray gun was installed in a 18m 3 robotized chamber designed for low pressure plasma spraying. Cold spray parameters involving 0.5MPa of air at 500°C and a corresponding gas flowrate of 18 m 3 /h were implemented at atmospheric pressure and also involving dynamic vacuum conditions in order to vary the impact conditions. For these latter, a continuous exhausting of the gaseous atmosphere was managed that corresponded to a measured chamber pressure stabilized at 3kPa during cold spray. Impact conditions were also varied by changing the spraying distances, respectively with 10, 40 and 80mm values.

Experiments to collect single isolated particles were implemented with the gun moving at 100mm/s and a 1g/min powder feed rate for both powders. After experiments weakly adhering particles on dusty samples were blown out by applying a gas stream using compressed air nozzle.

Observations and analyses: The flowabilities of the two batches of powders were assessed by Hall Flow method and their humidity rates were measured with humidity scale at 80°C. Thermo-gravimetric analyses (Setaram, Mougins-Sophia Antipolis, France) were implemented to complement the humidity tests. Specific surface area of each powder was measured by BET with nitrogen adsorption (ASAP2000, Micromeritics, USA). Bulk density of the agglomerates was measured by helium pycnometry (AccuPyc II 1340, Micromeritics, USA). X-ray diffraction (XRD) patterns for phase composition analysis were implemented on powders and coatings (D8 Discover,Bruker, USA) with Cu-Kα radiation and a 0-140° 2θ range. The crystallite size of each powder was estimated after Rietveld refinement of diffraction profiles using Le Bail method (Diffrac.Topas software, Bruker, USA).

Mean particle size of each batch of powder was measured by laser particle granulometry (Mastersizer 3000, Malvern Panalytical, Malvern, United Kingdom). Powders (free or cross-sectioned after resin mounting and polishing) and CS splats were observed by Scanning Electron Microscope (Nova NanoSEM 450, FEI, USA) using backscattered electron (BSE) mode. Crushed powders were also imaged by Transmission Electron Microscopy (Tecnaï 20F, FEI, USA) to observe agglomerates of grains. The Vickers micro-hardness of powders was measured on polished cross-section of resin mounted powders (AZ50-4 PRESI, France) with a 0.01kgf/mm 2 loading force. For these indentation tests, it was ascertained that indent sizes were at least two times smaller than the particle's diameter after cross-section. Thus, 20 indentations on several particles were made for each batch leading to indents diagonals ranging from 17 to 28 μm.

Flat-punch nano-indentation and micropillar compression experiments: Flat punch and micropillar compression tests were developed only on the 3YSZ powder. To that purpose, particles were prepared for in situ SEM nanoindentation experiments and also for micro-compression experiments on FIB-machined micropillars. Resin embedded Y-TZP particles samples of 5x5cm² with a thickness of 0.5cm were prepared using a diamond wire saw followed by polishing with SiC grit papers from P400 to P1200, and then 3µm and 1µm diamond pastes. Micro-pillars were machined by Focus Ion Beam (FIB) machining using a Thermo Scientific Helios NanoLab DualBeam microscope. First, high beam current (30 kV, 2.5 A) was used to dig a raw pilar shape followed by lower beam current (30 kV, 80 pA) in order to build a sharper and finer geometry of each micropillar. The pillar dimensions shown in Figure 1, are top 𝐷 𝑡 = 3.26µ𝑚, bottom diameter 𝐷 𝑏 = 3.61 µ𝑚 and height ℎ = 6 µ𝑚. These dimensions will be used for the numerical simulation. The yield surface of the model is assumed to be isotropic and includes two main segments, a shear failure surface Fs, and a cap Fc, which intersects the equivalent hydrostatic pressure axis (Figure 3). Within the yield surface the powder is purely elastic. The cap bounds the yield surface in pure hydrostatic compression, providing an inelastic hardening mechanism to represent the plastic nature of compaction. In addition, it controls the volume change, when the material yields by shear. The required softening is provided as a function of inelastic volume increase. To introduce better numerical stability a smooth transition between the two segments, an additional narrow transition region 𝐹 𝑡 is introduced (modified DPC model) [START_REF]ABAQUS 6.13 Theory Manual[END_REF].The Drucker-Prager Cap shear failure surface is written as:

𝐹 𝑠 = 𝑞 -𝑝 tan 𝛽 -𝑑 = 0
where 𝛽 is is the Drucker-Prager Cap friction angle and d describes cohesion. The cap surface is then written as:

𝐹 𝑐 = √( 𝑝 -𝑝 𝑎 ) 2 + ( 𝑅𝑞 1+𝛼- 𝛼 cos 𝛽 ) 2 -𝑅(𝑑 + 𝑝 𝑎 + tan 𝛽) = 0.
Here 𝑅 is a material parameter that controls the shape of the cap, 𝛼 is a small number used to define the smooth transition surface. 𝑝 𝑎 is an evolution parameter that represents the volumetric plastic strain driven hardening/softening: 𝑝 𝑎 = 𝑝 𝑏 -𝑅𝑑 1+𝑅 tan 𝛽 . The hydrostatic compression yield stress 𝑝 𝑏 is a function of volumetric plastic strain 𝜀 𝑣 𝑝 , which can be expressed as:

𝜀 𝑣 𝑝 = ln 𝜌 𝜌 0
where 𝜌 is the compact relative density and 𝜌 0 the initial relative density. The transition surface is defined as:

𝐹 𝑡 = √( 𝑝 -𝑝 𝑎 ) 2 + (𝑞 -(1 - 𝛼 cos 𝛽 ) (𝑑 + 𝑝 𝑎 tan 𝛽)) 2 -𝛼(𝑑 + 𝑝 𝑎 tan 𝛽) = 0

Results and discussions

Powders analyses

Powders architectures: The powders having already been studied in [START_REF] Celeste | Investigation of Agglomerated and Porous Ceramic Powders Suitable for Cold Spray[END_REF], only results about batches and are reported here. The typical features observed by SEM and TEM are summarized for as atomized and powders in Figure 4. The two agglomerated ceramic powders exhibit particles having a spherical shape and a smooth surface due to the nano-sized and ultra-fine grains. However, some particles have a "donut" morphology which is induced by drying instabilities during atomization. Such defects are not of major concern for a melting process but shall be probably better controlled for a spraying process. Cross-sectioned particles at low and high magnification show the homogeneity and the high compactness of the agglomerated nanostructure. Some micro/nano-pores are present but are difficult to quantify by image analysis and conventional metallography. In case of yttria powder (Figure 4), it is obvious that the architecture is different, much finer than the zirconia powder but exhibiting a rather heterogeneous distribution of nano-sized grains and some coarser agglomerates in the micrometric range. Such architecture led to both nano-sized pores and larger ones. The XRD analyses and the TEM images allow to better estimate the actual size of the grains or crystallites. Two typical morphologies were observed: grains with faceted edges, regular diffraction contrast for 3YSZ and aggregates with more rounded contours, irregular contrast, enclosing nano-pores for Y2O3. Powders characteristics: The two different powders were analysed to investigate structural, physico-chemical, and mechanical characteristics as summarized in Table 1. Both powders exhibited a similar range of particles size with a mean diameter between 35-40µm. They were both relatively sensitive to humidity therefore pre-heating at 80°C of powders was necessary before and during spraying experiments to improve the powder flowability and prevent detrimental clogging. Phase compositions were analysed by XRD. The as-atomized zirconia powder with yttria addition (3% mol.) was 43.0% tetragonal (t-ZrO2) and 57.0% monoclinic (m-ZrO2). Pure yttria powders were cubic (c-Y2O3). The corresponding bulk densities measured by He pycnometry were 5.94g/cm 3 for 3YSZ and 4.48g/cm 3 for Y2O3. For 3YSZ, the bulk density was only a few percent below the theoretical density but for yttria a higher difference was measured. This difference is probably due to a difference of internal architecture that is also shown by comparing the specific surface area which is two times higher for yttria (19.78m 2 /g) compared to zirconia (10.78m 2 /g) and respectively. Such difference in architecture is also evidenced by a significant difference in crystallite sizes respectively at 79 nm for zirconia and 51 nm for yttria. Because of the porous and agglomerated structure, the micro-hardness of both powders are very low and nearly similar values within 35-40Hv0.01 were measured for both powders.

"Splat" experiments

In previous work, particle velocities involving same LPCS CS parameters and powders were all measured to be greater than 350m/s in the central part of the jet and for spraying distances of 80mm and shorter one's [START_REF] Celeste | Investigation of Agglomerated and Porous Ceramic Powders Suitable for Cold Spray[END_REF]. For example, at 40 mm, particles velocity of 450m/s has been measured for yttria. It is therefore assumed (not measured) that an even higher velocity is obtained at 10 mm. These ranges of particle velocity and spray distance are conventional in cold spraying. However, with such small spraying distance, especially at 10mm, the bow-shock effect may affect drastically the actual impact velocity. In our work, thin films were obtained with both powders but with greater thickness and cohesion in the case of yttrium powder [START_REF] Celeste | Investigation of Agglomerated and Porous Ceramic Powders Suitable for Cold Spray[END_REF]. In this paper, it is aimed to better understand whether the bonded particles deform and fragment by examining individual particles. To this end, both powders were sprayed at atmospheric pressure (100kPa) while yttria powder was also sprayed under dynamic vacuum (3kPa). Same cold spray parameters involving 10mm and 40mm spraying distances to achieve isolated yttria and zirconia particles deposited on A2017 substrates for further observations by SEM with secondary electron detector. Representative images are given in Figure 5 for each spraying distance. According to the SEM views shown in Figure 5, splats do not have the same flattening behaviour depending on the type of powders, spraying distances and atmosphere. First, isolated zirconia particles (Figure 5, A) were generally much less present than the yttria particles (Figure 5, B) at atmospheric pressure. Despite, fewer bonded splats can be observed on the substrate for zirconia compared to yttria, it was obvious that zirconia particles were fragmented but rather undeformed, i.e., keeping the original spherical shape close to the D50. From these characteristics, it can be deduced that most of the zirconia powders were in fact weakly bonded due to the effect of the bow-shock, but more likely also intensively blown by the cold spray gas stream during the process. At 40 mm, some flattening of the zirconia particles and also fragmentation, i.e small islands around a bigger one was observed. In addition, some submicrometric fragmented 3YSZ grains are also similarly dispersed and stuck on the surface for both spraying distances.

The features of yttria by LPCS at atmospheric pressure (Figure 5, B) are significantly different from those of the zirconia powder (Figure 5,A). From the observation at 10mm and 40mm, it is obvious that flattened yttria particles are more numerous especially for the shorter spraying distance. Yttria particles adhere to the substrate exhibiting a typical volcano-like shape with size roughly ranging from 5 to 30µm. The particles appear deformed and fragmented but obviously more compact than 3YSZ powder after impact. At 40 mm, similar morphologies of volcano-like splats and fragments were observed but less concentrated probably due to the widening of the stream. These splats experiments show the actual difference in spreading behaviour between both powders.

Yttria particles sprayed under dynamic vacuum (Figure 5, C) appear much more fragmented. Indeed, if some isolated splats, rather rounded may be found, it was remarkable that small grains have spread homogeneously over the substrate surface as shown at a spraying distance of 10mm. It results in a rather homogenous film than isolated splats. At 40mm, such film is less dense probably due to the widening of the jet. Such spreading behaviour under low pressure condition is therefore more govern by a micro-fragmentation process compared to an actual deformation-fragmentation evidenced at atmospheric pressure. The potential fragmentation of the powder before impact during the flight of the agglomerated powder within the supersonic stream might be questioned but also the role of the surrounding pressure on the bow-shock that could prevent very small particles grains to reach the substrate.

Flat-punch indentation and micropillar compression experiments

Load-displacement curves of three different 3YSZ grains are given in Figure 6. Grain 2 and 3 were corresponding to the monotonic loading condition while grain 1 underwent a cyclic loading with increasing depth. From Figure 6, it is obvious that the measurements on were nicely repeatable and therefore relevant with the actual behaviour of the powder. A depth of around 3µm was measured by the tip for a load of 57mN. The flat punch indentation cyclic tests reveals that the material has an elastic and some "plastic" deformation behaviour (elliptical shape is formed during the discharge). Such behaviour corresponds to the non-reversible densification under compression of the agglomerated material. It was also observed on SEM images that the compaction was enabled mainly in the loading direction without evidence of boundary effects that could promote out-of-plane (pop-up) displacement. 7. Pillar 2 and pillar 3 were corresponding to the monotonic loading condition while pillar 1 underwent a cyclic loading with increasing depth. From Figure 7 it was obvious that the deformation behaviour was similar up to 1mN but when increasing more, a peak load always occurred but with different maximum force respectively 1.42mN and 2.02mN for pillars 2 and 3 that corresponded to a stress of 153MPa and 210MPa respectively. It is also noticeable that this maximum peak load that was measured for pillar 3 was nearly similar to those of pillar 1 upon cyclic loading. For deeper displacement, both pillars 2 and 3 under monotonic loading exhibited the same behaviour with a final force of around 1.18mN, which corresponded to a stress of 126MPa. The first ramp of the curve recorded for each pilar was similar and showed an elastic behaviour, then plastic deformation and strain hardening appears to take place at low displacement, observed by a second ramp between 200nm and 300nm. This kind of plastic deformation (compaction) was also ascertained by the cyclic micro-compression test of pillar 1 for which ellipses were monitored during the discharge. During these first two phases, the SEM images showed a compression mainly on the top of the pillars. Just after this local plastic deformation, a decrease in force is monitored for all pillars. This part might be considered as a pseudo softening. In fact, this phenomenon reflects a damage starting with the slipping of the top of the pilar and ending by a failure of the pillar as shown in Figure 7. An identification procedure of DPC parameters using the numerical model involving the actual pillar geometry and the surface of a grain for flat punch compression was implemented in comparison to the experimental loaddisplacement curves obtained with the pillar 2 and grain 2 over a period of 15sec (maximum depth 15 nm). The resulting numerical load-displacement curves obtained with the identified parameters are presented Figure 8 according DPC parameters that were determined empirically in a first approach (Table 2) and will be further numerically optimized (optimization loop). For the flat punch test, comparison of the numerical load-displacement curves with the data shows a good agreement. However, the discrepancy between 0.4 and 0.8µm displacement may be improved by a better adjustment of the DPC parameters in order to better fit with the actual displacement when the powder grain starts to compact. Normally, this adjustment would also improve the fitting of the behaviour above 0.8 µm.

Using the same material's data for the modelling of micropillar compression, a good agreement is also observed up to 0.2µm, which corresponds to the elastic and plastic part of the material behaviour. Above this value, the data of the first approach of the DPC model is not relevant and shall be improved by adjusting the Cap plasticity first and the Cap Hardening in both models. The difficulty is to simulate that the densification becomes significant only once pillar height has been reduced by more than a half, i.e., when the pillar has been significantly strained. In addition, the main limitation of the model is the fragmentation (damage model) that is not included in the DPC model.

Conclusions

In this work, two different agglomerated ceramic powders were analysed in order to investigate the role of their architecture on the impact behaviour during cold spray. As-atomized zirconia and yttria agglomerated powders were with different characteristics: especially in terms of porosity, specific area, crystallite sizes. Splat experiments were carried out in order to better understand the impact behaviour of bonded particles experimentally. The clear evidence of the fragmentation and deformation of the agglomerates has been observed leading to the bonding of the particle. Differences in the resulting architecture after impact are found depending on the nature of the powder but also depending on the spraying atmosphere. Yttria appears to be the powder with a better ability to "room temperature compaction impact" (RTIC). Under dynamic vacuum, highest fragmentation was enabled leading to deposition of very grains with a much more efficient and homogeneous that could explain why coatings by cold spray could be obtained more easily with this powder exhibiting a porous architecture with 50nm crystallites size leading to a large surface area of 19.8 m²/g.

In parallel, microcompression experiments on three different 3YSZ micropillars and flat punch experiments on three different grains of 3YSZ powder were carried out. These experiments demonstrated the plastic deformability of the zirconia powder that correspond to the ability to compact. In a first empirical approach, a first set of parameters in order to implement a Drucker-Prager Cap material behaviour for agglomerated powders under quasi-static compression has been developed. A numerical fitting of these parameters using an optimisation algorithm based on a Levenberg-Marquardt minimisation is on progress. If successful, such model could be then implemented in single particle compaction model using similar quasi-static loading condition.

Figure 1 .

 1 Figure 1. SEM overall and detailed views of FIB-machined micropillars of 3YSZ powderMicro-compression experiments were achieved using an in-situ SEM indenter (ASA, Alemnis AG, Bern, Switzerland), first developed by Rabe et al.[START_REF] Rabe | Observation of fracture and plastic deformation during indentation and scratching inside the scanning electron microscope[END_REF]. It is installed in a Zeiss DSM 962 SEM. In situ SEM indentation allows real time monitoring and visualization of material's deformation under tip-loading. The nano-tip is displacement-controlled (piezo actuator) with a feedback loop control. Displacement-controlled devices allow load jumps to be avoided during micro-pilar compression of brittle materials, which can occur during load-controlled tests. A more detailed description of the SEM indenter can be found in[START_REF] Rabe | Observation of fracture and plastic deformation during indentation and scratching inside the scanning electron microscope[END_REF]. A 25µm diameter flat punch was used for nano-indentation on flat cross-sectioned powder. All the experimental compressions were performed with a tip displacement rate of 100 nm/s. Three micro-compression experiments were achieved on three different micropillars. Two experiments with similar loading conditions and a third one with a series of loading-unloading conditions. The same protocol was implemented for flat punch experiments on three different cross-sectioned particles. With such loading conditions, the maximum in-depth displacements were monitored in the range of 1µm to 4µm. Due to the low displacement rate, series of SEM images were recorded to follow the behaviour of the material during the nano-indentation and micro-compression experiments.Finite Element Analysis of micro-compression tests: ABAQUS/Standard is implemented to model the flat-punch nano-indentation and micropillar compression experiments. Because of axial symmetry, only half of the sample geometry was meshed using 4-nodes bilinear, hybrid with constant pressure (CAX4H) mesh. Mesh density near the contact surfaces and geometrical singularities was increased. Punch was modelled as full-rigid body with a hard contact boundary condition at the powder/tip interface. Since the DPC model has no rate dependent terms, the FE simulations are considered in a quasi-static loading regime. In actual experiments, as well as in FE simulation, a pillar was dimensioned with top 𝐷 𝑡 = 3.26µ𝑚, bottom 𝐷 𝑏 = 3.61 µ𝑚 diameters and height of ℎ = 6 µ𝑚. The compression step is modelled by applying a vertical 100 nm/s displacement to the flat punch with a step duration of 15s. Meshed models are shown in Figure2.

Figure 2 . 3 ( 2 (Figure 3 .

 2323 Figure 2. Finite element models for micro-compression tests: micropillar (left), flat punch (right)

Figure 4 .

 4 Figure 4. (left) 3YSZ, as atomized; (right) Y2O3, as atomized.

Figure 5 .

 5 Figure 5. 3YSZ and Y2O3 splats for atmospheric (A and B) and Y2O3 for dynamic vacuum (C) conditions at 10mm or 40 mm spraying distances

Figure 6 .

 6 Figure 6. Load-displacement curves of flat punch indentation on three different grains Load-displacement curves of three different 3YSZ micropillars are given in Figure7. Pillar 2 and pillar 3 were corresponding to the monotonic loading condition while pillar 1 underwent a cyclic loading with increasing depth. From Figure7it was obvious that the deformation behaviour was similar up to 1mN but when increasing more, a peak load always occurred but with different maximum force respectively 1.42mN and 2.02mN for pillars 2 and 3 that corresponded to a stress of 153MPa and 210MPa respectively. It is also noticeable that this maximum peak load that was measured for pillar 3 was nearly similar to those of pillar 1 upon cyclic loading. For deeper displacement, both pillars 2 and 3 under monotonic loading exhibited the same behaviour with a final force of around 1.18mN, which corresponded to a stress of 126MPa. The first ramp of the curve recorded for each pilar was similar and showed an elastic behaviour, then plastic deformation and strain hardening appears to take place at low displacement, observed by a second ramp between 200nm and 300nm. This kind of plastic deformation (compaction) was also ascertained by the cyclic micro-compression test of pillar 1 for which ellipses were monitored during the discharge. During these first two phases, the SEM images showed a compression mainly on the top of the pillars. Just after this local plastic deformation, a decrease in force is monitored for all pillars. This part might be considered as a pseudo softening. In fact, this phenomenon reflects a damage starting with the slipping of the top of the pilar and ending by a failure of the pillar as shown in Figure7.

Figure 7 .

 7 Figure 7. Load-displacement curves of flat microcompression tests on three different micropillars 3.4 Material's parameters identification of a Drucker-Prager Cap (DPC) model

Figure 8 .

 8 Figure 8. Experimental and numerical load-displacement curves obtained after first approach of parameters identification (left) for a flat punch experiment (right) for a micropillar experiments

Table 1 . Powders characteristics

 1

	Powder type	ZrO2	Y2O3
	Mean diameter, µm 39.9	36.0
	Humidity rate, %	0.2	0.39
	Hall Flow., s/25g	82	61
	He density, g/cm 3	5.94	4.48
	Composition, %	43.0 tetragonal 57.0 monoclinic	100.0 cubic
	/theoretical, %	99,7	89.4
	Surface area, m 2 /g 10.78	19.8
	Crystallite size, nm 79	51
	Hv0.1	33±6	39±5

Table 2 . Drucker-Prager Cap initial data (first approach)

 2

	Cap plasticity

Acknowledgments

The authors would like to thank the ANR (French Agency for Research) and all the academic and indutrial partners of the CERASOL project (ANR-19-CE08-0009): IRCER (Limoges, France), Nanoé (Ballainvilliers, France) and Medicoat France (Etupes, France), especially D. Chatelain at IRCER for his help to analyse the powders. The following persons at MINES-PSL are gratefully acknowledged for their help for XRD analyses (C. Monteiro), TEM images and analyses (M. Sennour), cold spray experiments (J.-D. Bartout and F. Borit).


Pierre Evesque

Angel Garcimartin

Diego Maza Ozcodi

Nicolas Vandewalle

Yves Garrabos

Carole Lecoutre-Chabot

Daniel Beysens

Xiaoping Jia

Meiying Hou

Scientific goals of the topical team on vibration in granular media : (the physics with the fure VIP_Gran Instrument)

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

Fig. 5 Chinese satellite cell in Airbus; gravity direction is horizontal (when it is different from 0); vibration direction is horizontal. Area fractions for the 4 cells are 43%, 56%, 78% and for the large particle in the mixture is 14%, as indicated in Fig5.e.

Sa. Test of Chinese satellite cell

Conceming the Chinese satellite cell, different filling was used in each compartment, which can be measured from the cell at rest (Fig. 5a). Sorne preliminary conclusion is illustrated in Figure 5. One notes from comparing Figs. 5a & 5b that grains are agitated by vibration. Also, one sees frorn Fig. Sb, that the agitated medium at 2g does not expand so much and remains closed to the "bottom wall" (i.e. to the left wall); it does not occupy the whole available space and �a. large free volume exists on the right part of the tompartments. This is not the case for the 3 densest • cells at 0g with high vibration intensity as shown in Figs.

Sc & 5d, for which granular medium expends and occupies unifonnly the "maximum" available space instead of re�naining in a cluster, as in Fig. 5e, when either excitation is not large enough to break the cohesion, or when the gravity is playing a role as in Fig.

Sb. It is to note that in Figs. Sc & 5d with large excitation in microgravity, one observes some crystalline order in the bottom right compartrnent, while the system looks much more random in the top right and bottom left compmiments, as if particles could move erratically from one location to the other in these two last compaiiments, while they were confined in a cage in the first compartment. We confim1 this using spatial Fourier transform; it was found the persistence of a global crystalline structure in the densest cell (80% area-filling ratio ) in 0g, while this order disappears in 0g in the 60% cd!, proving the "liquid-or gas-like" structure.

The top-left compaiiment was dedicated to study binary compositions with 2 kinds of balls havin g different sizes. Do these particles mix easily or segregate by size? We observed localized zones of large density with large balls disperse in rather low concentration of small pmiicles; the position of the "cluster" of large paiiicles is found to fluctuate with time, probably sensitive to g-jitter.

Besides, we obtained the acceleration threshold needed to generate the ball vibration in preparation for the satellite experiments. More careful analyses of the data are still undergoing for further understanding of our results.

Sb. Rattle effect due to g-jitter:

► Study of the effect of g-jitter with the 2d cell of the French European team (Lw*h=29. 9* 9mnl) We have tried to study the effect of g-jitter using the 2 d sub-cell of the Maxus 7 rocket cell (cf. Fig. 2). It has been found that the gas cannot be fom1ed if g-jitter is too large and we see some erratic rattle effect. It means that the grains move as a whole from one wall to the other due to a small remaining gravity which changes of direction erratically.

On the contrary, when vb = Aco is large enough, where Ai s the amplitude and f = co/(2n) is the frequency of vibration, gas fonns and the g-jitter becomes negligible.

A way to analyse this effect is to compute the position R=(X,Z) ôf the centre of mass of the gas as a fonction of time t and to measure its standard deviation !J,,Z. If it is of the order �Z = L/2 (L being the cell length), we see a rattle effect: the mass centre of the balls goes from one end of the cell to the opposite one. On the other hand, if !J,,Z is much smaller than L then we get a "gas", whose internal "pressure" stabilises the mass centre in the middle of the cell; and the larger tl 1 è "pressure" the smaller the fluctuations of i6.R However!J,,Z cannot be smaller than the typicè:l fluctuations of the centre of mass of a gas containing \ balls, i.e. L/(2N\ (if one excepts cases when sornè electrostatics takes part). The analysis is cone f orn tb:: ' cam video.

In Fig. 6 we present 3 different curves representin'. c.. the evolution of the Z coordinate of the centre of mas as a fonction of tiine during the period of micro-gravit: of 3 different parabolas. We see for one of it the rattk effect; in this case Z goes from one edge to the other. 01, the other hand, for the two other curves, Z remains il' the vicinity of the cell centre, which corresponds to ,, gas-like behaviour. The difference between these t\,vc behaviours can be measured using the standard deviation f:...Z of the Z evolution. So each curve of Fig. 6 gives a single data point f:...Z. The measurement of the relative influence of g-jitter and vibration intensity is shown in Fig. 7, where f:...Z is plotted as a fonction of the vibration parameter vb 2 =(2rcAf) 2 , for all parabolas. As data fall on a single curve, it means that 2nAf is the right parameter. The transition from rattling to granular gas is observed; however, it is broadened since the real amplitude of g-jitter fluchiates depending on the exact condition of parabola. ► Auto matie measurenzent of the centre of mass in one of the 4 sub-cell of the satellite SJ-8 cell It is important to be able to treat such data automatically. This is why we have programmed an automatic procedure in Java which can be nm inside the ImageJ program and which allows getting the position of the centre of mass in a cell of which we define its boundary. We could apply this procedure/macro in the case of the SJ-8 cell filled with a small number of grains. The cell for which we studied the content motion is the bottom right one in Fig. 8.

The result is repo1ied in Fig. 9, where we have plotted the evolution of the centre of mass (given by its coordinate (Xg,Y g) during a parabola. Obviously, we see also the rattle effect.

Conclusion

Through these examples we have proved that mechanics of granular matter can be investigated in microgravity. This is a puzzling challenge, since granular matter is dangerous to handle in space environment, because grains or powders are dangerous to breathe, and because any lever/buttom can get stuck by a grain in bad position. On the other hand their manipulation is unavoidable, since they enter in most human activities. In particular, why do we need to grow plants in weightlessness condition, if we are not able to process them, to eut them in pieces or to collect and use their seeds ... if.

We do not know at the moment if we can extrapolate the behaviours found on emih. However, we lrnow that these earth behaviours are quite sensitive to details, due to the strong non linearity of the law of solid

FigFig. 5d :

 5d Fig. Sa: 2g, no vibration

Fig. 8

 8 Fig. 6 Z-position of the mass1centre vs. time t in the Maxus� 2 d cell during an Airbus parabola (green: 0.95rn.m,125Hz; black: 0.047mm 25Hz ; red 0.28mm 160Hz)

Fig. 9

 9 Fig. 9 Evolution of the centre of mass position of coordinates (Xg, Y g) during a parabola when excitation is small, in the case of the bottom right cell of Figure 8


Bruce Ayache

Use of a free and open access high

Use of a free and open access high-resolution Digital Terrain Model for the identification of surface karst forms

AYACHE Bruce*, CABARET Olivier* *BRGM Nouvelle-Aquitaine : b.ayache@brgm.fr; o.cabaret@brgm.fr

The typical geomorphological forms of karst such as dolines or poljés can play an important role in surface runoff by constituting preferential infiltration points for rainwater directly towards the water table. Their identification is therefore important to evaluate the modalities of groundwater recharge, the orientation of the current and past drainage axes within the aquifers and also to evaluate the groundwater vulnerability. As such, many multi-criteria methodologies (Paprika, RISK, etc.) include this indicator of surface karstic forms presence in the vulnerability maps of water catchments.

Their identification and characterization (depth, asymmetry, nature of the bottom, etc.) is however delicate and tedious since it is often based on the field reconnaissance which is long and dependent on soil conditions (presence of vegetation or crops). The resulting mapping is rarely exhaustive. However, the democratization of LiDAR surveys offering high-resolution digital terrain models paves the way for semi-automatically, quickly and over a much larger area detection of these shapes.

On the territory of the Eaux-SCARS regional project (https://sigesaqi.brgm.fr/-Projet-Eaux-SCARS-.html), aiming to understand the functioning of the CArbonate aquifers of the north aquitain Basin in France and in particular the conditions of surface infiltration towards the aquifers. The DTM HR, resulting from Lidar surveys, called RGE Alti V2® and made freely available by the French National Institute of Geographic and Forest Information (IGN), could be used to establish a first inventory of the dolines.

A methodology has been developed to identify the hollows by calculating the contour lines at 1m intervals. These hollows are then qualified in order to distinguish those likely to be real dolines by using the Miller circularity index, their proximity to the building or the road network, the latter being able to cause dips that do not correspond to dolines. Beyond this identification, it is possible to characterize their average and maximum slope, their orientation or their geology.

This method has been compared with others (Cartannaz, 2015) and the results confronted to inventories and maps obtained from bibliography and field work. The results show the potential of the method to improve the knowledge of the study area karst geomorphology and characterize the vulnerability of aquifers.

Beyond the method, it is worth highlighting the use of the RGE Alti V2® offering a high-resolution DTM over the whole of France and allowing the method to be applied to departmental extensions at a lower cost and without the need to carry out an expensive and localized lidar survey.

Nearly 15,000 potential dolines have thus been identified over the 22,000 km² of Eaux-Scars territory and provide decision support map. Their validation must be continued in order to be able to use it in the future. However, the use of these data seems promising to improve the location of the various geomorphological forms, to obtain a large-scale inventory and to identify forms invisible to the naked eye in the field.


Esra Orucoglu
email: e.orucoglu@brgm.fr

Sylvain Grangeon

Alexandre Gloter

Jean-Charles Robinet

Benoît Madé

Christophe Tournassat

Competitive sorption processes at clay surfaces: Experimental and modeling approaches

Keywords: Adsorption, Competition, Surface complexation modeling, Clay, Montmorillonite

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