Ana M González
email: anagonzalezram@uoc.edu

Beatriz Revelles
email: brevelles@uoc.edu

Elisabet Almeda
email: elisabet.almeda@ub.edu

Núria Vergés Bosch

José S García

Women in ICT: Opportunities for Their Inclusion in An International Labor Market

Keywords: Female talent, incorporation of women in ICT, labor conditions, employment

ICT is a key sector for developing contemporary economies and it entails an opportunity for increasing the employment rates internationally. Women were traditionally underrepresented; therefore, we need to reinforce their role in the international labor market. Before the implementation of positive actions, we need to know what is the situation and experiences of women in ICT workplaces. Through the Spanish Labor Force Survey we analyze the evolution of women. Despite the economic crisis, data shows that women have as good job prospects as men in the ICT labor market. However, women present higher levels of qualifications than men in the same category which may be interpreted as a sign of gender discrimination. Significantly, women display more critical opinions regarding the average work week.

Introduction

The low number of women in ICT was widely discussed in the literature [START_REF] Cockburn | Brothers: Male Dominance and Technological Change[END_REF][START_REF] Kvande | In the Belly of the Beast: Constructing Feminities in Engineering Organizations[END_REF][START_REF] Margolis | Unlocking the Clubhouse Women in Computing[END_REF][START_REF]La segunda brecha digital[END_REF] as a dysfunction of the education and the labor market. The lack of women in these areas evidences social injustice, particularly, in regards to the importance and great opportunities of the ICT sector for future employment [START_REF]Encouraging STEM Studies for the Labour Market´[END_REF][START_REF] Gill | Cool, creative and egalitarian? Exploring Gender in Project. Based New Media Work in Europe[END_REF]. Apparently, women are less attracted compared to men, as shown by the low number of women in the ICT workforce. Male predominated professions tend to create unfriendly environments for the few women in the workplace. Literature attributes this as the primary cause of the exclusion of women from ICT sectors [START_REF] Rommes | Design and Use of Gender Specific and Stereotypical Toys[END_REF][START_REF] Cockburn | Brothers: Male Dominance and Technological Change[END_REF][START_REF] Bystydzienski | Removing Barriers[END_REF]. This work attempts to shed light on the situation of women in the Spanish labor market in relation to ICT employment. The role of women in the labor market, not specifically in ICT sector, has been traditionally linked to insecurity and poor conditions because women hold subordinate positions. In this work, we examine to what extent male and female employment shows similar characteristics, or otherwise, in the ICT sector. The incorporation of women in the labor market has to do with maternity and second shift [START_REF] Hochschild | The Second Shift[END_REF]. Labor conditions within the ICT sector affect women seriously, because they require total availability, long-hours and extra work, making difficult a work-life balance [START_REF] De La Rica | Segregación ocupacional y diferencias salariales por género en España: 1995-2002[END_REF].

During the last decades, multinational corporations have implemented programs to mentor and attract women in their professional staff. However, positive actions have shown limited results [START_REF]Encouraging STEM Studies for the Labour Market´[END_REF]. The percentage of women in private organizations remains relatively low, around 20%, and they occupy management and commercial positions rather than technological ones. It seems some positions are still male predominated. Therefore, we need to collect more information about how to tackle female barriers in the workplace and create more attractive environments for women in ICT sector. We need to send positive messages to women in STEM (science, technology, engineering and mathematics) in order to facilitate their incorporation into the ICT sector [START_REF] Etzkowitz | Athena Unbound: The Advancement of Women in Science and Technology[END_REF]. Role model programs are encouraging women in university but the low number of women is still a problem. Likewise, managers in the TIC sector show an increasing interest to including women, as such female talent has value for them [12]. We need to know more information about the perception of women towards the ICT employment. Female opinion about their labor conditions provides information about what problems are perceived as obstacles due to gender issues. The Labor Force Survey is an international survey that explores labor participation across 28 Member States of the European Union [13].

The paper comprises three sections. In the first section we introduced the article. In the second section we present the objectives and methodology. The third section explores the situation of women in the ICT sector and the main findings of our work. Finally, we summarize the main conclusions of this paper and make some recommendations for future implementation in education and business organizations.

Objectives and methodology

The objective of this work aims to provide feasible data about the participation of women in the ICT workforce. This work analyzes working conditions of women in the ICT sector according to the Spanish Labor Force Survey. This survey is a large household sample survey providing quarterly results on labor participation of people aged 15 and over as well as on persons outside the labor force. European countries provide information about their national labor workforce in accordance with Council Regulation (ECC) No. 577/98 of 9 March 1998. From the application of this survey, the microdata contain information about several dimensions of labor conditions, unemployment situation, in a representative sample per regions, as well as sectors of activity. Spanish Labor Force Survey covers 60.000 households and 150.000 people. Some methodological notes about the ICT sector are necessary for understanding the findings of this study. We use the classification of technological occupations (National Classification of Occupations CNO) by the National Institute of Statistics, as proposed by the ILO in 2011. Occupational categories cover professionals in information technology (code 27 of the National Classification of Occupations (CNO) 20) which comprise analysts and software designers and multimedia specialists in databases and computer networks; technical positions in science and engineering (code 31); technicians and information technology and communications (code 38) that comprise operations and information technology user support, computer programmers and technicians in audiovisual recording, broadcasting and telecommunications.

Women in the ICT labor market

ICT employment is a relative small percentage of the total Spanish employment (4%). This sector of activity only represents 1.4% of the workers; however, the importance of the economic sector increases the relevance for the workforce. The representation of women in these groups of occupations is very limited 0.6% in comparison with men, which is2.1% of the total population. Women represent around 24% of the total employees in the ICT sector. A characteristic of this sector is the high rate of employment for both men and women professionals which supports the hypothesis of good expectations of employment for male and female workers. According to the Labor Force Survey in 2015, the unemployment rate (people in ICT sector who left the labor market last year) reaches 3.2%, similar for men and women in the workforce. Employment and unemployment rates from 2008 to 2013 in the ICT sector show a steady situation, even if Spain was severely affected by the economic crisis, ICT employment displays a positive evolution. The economic crisis destroyed 3.5 million jobs, mostly in two activity sectors 'building construction' and 'specialized construction activities'. Consequently, the ICT sector presents a healthy situation that positively affects male and female workforce. Table 1 presents rates of employment of men and women and shows a gender gap in the ICT sector. The percentage of women is smaller than men in every age group as a result of low female presence generally. Additionally, the female workforce displays different percentages in occupation rates between age groups. Women between 46-64 years old have the lowest percentages (0.6%) which reflects a historical underrepresentation of women in the ICT sector. The youngest women (25-30 years old) are 2.5 less represented than men in the same age group. This data suggests that there is as low integration of women in the ICT labor sector despite an increasing number of female graduates. These results indicate that the implementation of positive actions is necessary for the inclusion of women in ICT environments. We have looked at employment security in the ICT labor market from a gender perspective. Table 2 displays gender differences in ICT employment. The results indicate similar percentages of men and women with regard to temporary employment and part-time employment. In the case of temporary employment, women show a slight difference (13.8% men; 15.8% women) but the effect is very small and lacks statistical significance. Parttime rates are similar to men and women rates from other sectors. However, we explore reasons why men and women are part-time employees, displaying women argue family to a greater extent than men (33.5% women; 4.5% men). Working long hours is identified as a factor which contributes to creating an unfriendly environment in the ICT sector [START_REF] Faulkner | Nuts and Bolts and People: Gender-Troubled Engineering Identities[END_REF][START_REF] Faulkner | Doing Gender in Engineering Workplace Cultures: II. Gender In/Authenticity and the In/Visibility Paradox[END_REF][START_REF] Faulkner | Can Women Engineers be 'Real Engineers' and 'Real Women?' Gender In/Authenticity in Engineering[END_REF]. The percentage of employees working overtime in the ICT sector is higher than in any other activity sector, although men and women work the same amount of extra hours, with being slightly higher (9.5% men; 9.8% women). This indicates that women undertake the same work as men and is disadvantage for professional mothers [START_REF] Cockburn | Brothers: Male Dominance and Technological Change[END_REF][START_REF] Margolis | Unlocking the Clubhouse Women in Computing[END_REF][START_REF]La segunda brecha digital[END_REF]. According to the Labor Force Survey 2015, women would like to work fewer hours than they actually do, even accept a pay cut. The Labor Force Survey asks questions about preferences for working hours and the willingness to accept a reduction in wages. Findings show that 9.8% of women would accept a reduction in working hours compared to 4.6% of their male counterparts. Moreover, 64.2% of women would prefer to accept pay cuts, while 56.7% of men would be willing to accept to work more hours than women in the ICT sector. The survey shows gender differences regarding the work attitudes and life styles of men and women. Results suggests that women suffer severely the long working hours in the ICT sector, since they accept lower wages instead of spending more free time outside work.

Men

We identify that a work-life balance is as a handicap for the female workforce [START_REF] Margolis | Unlocking the Clubhouse Women in Computing[END_REF][START_REF]La segunda brecha digital[END_REF][START_REF] Hochschild | The Second Shift[END_REF]. Despite the effectiveness of positive policies, women are negatively affected by social gender roles that continue distributed traditionally.

In relation to family care, the Labor Force Survey includes some questions that allow us to know how men and women are living with children under 17 years old. As a result, we know how family matters in the distribution of male and female workforce in the table 3. The data show that there is not a difference between men and women with children under 17 years old in the ICT sector (42.5% men while 47.7% women). These results suggest that women still have to compromise time for care, although we do not know the extent of coresponsibility at home nor the effect on external support for housekeeping. Previous studies suggest that women have to make greater efforts than men to achieve similar positions in professional careers because male dominated environments discourage women from pursuing higher milestones. In addition, they indicate that female work is undervalued because of gender stereotypes [START_REF] Kvande | In the Belly of the Beast: Constructing Feminities in Engineering Organizations[END_REF][START_REF] Etzkowitz | Athena Unbound: The Advancement of Women in Science and Technology[END_REF]12,13,[START_REF] Faulkner | Nuts and Bolts and People: Gender-Troubled Engineering Identities[END_REF][START_REF] Faulkner | Doing Gender in Engineering Workplace Cultures: II. Gender In/Authenticity and the In/Visibility Paradox[END_REF]. We examine the academic credentials in the male and female workforce, checking whether women need to demonstrate greater merit than men to achieve the same position on the professional ladder. Some questions of the Labor Force Survey point to indirect ways to investigate overqualification. Data from Labor Force Survey 2105 suggest that women are more qualified than men in the ICT sector using two different indicators. Firstly, we compare overqualification by measuring more than one standard deviation from the average years of schooling by total population included in the occupation category. Through this indicator, women in the ICT sector display overqualification because they show an almost doubled ratio (19.4%) to their male counterparts (10.7%) in each sex group category. Secondly, we compare overqualification as a deviation of the average number of schooling years. According to this second indicator, data shows that 17.7% of women (while 13.3% of men) complete more years in school than the general population. There is gender statistical significance but the relationship between both variables (sex of workers and schooling years) is weak.

Conclusions

The results of this work confirm our primary findings of qualitative studies [START_REF] Vergés | Doing and Undoing Genders and Information and Communication Technologies[END_REF], concerning major obstacles faced by women in male predominated environments. The main problem suggested by responses from women interviewees in the Labor Force Survey is the time demanding environment of the ICT sector. The findings show women would accept lower wages to reduce their working schedule. Women are critical of the length of the work by week in the ICT sector. We can suggest that working hours are more stressful for women than men because of their impact on the work-life balance. The labor Force Survey shows similar percentages of male and female workers in the ICT sector with children living at home under 17-year-old, which suggests female double shift. The long-hours climate in the workplace probably clashes with care roles at home. It would be interesting to compare differences between countries regarding diverse culture and persistence of gender roles. A future line of research will provide more evidence about northern and southern countries regarding motherhood and professional orientation of women by countries.

This work also confirms the opportunity offered by the ICT sector for qualified women. Firstly, the employment rates should be an incentive for women who have higher percentages than men in unemployment rates (although it depends on wiping out gender bias in the workplace). The ICT sector was affected in a lesser extent by Spanish economic situation, maintaining employment rates and labor conditions compared to the rest of the economic activity. Unlike building, construction and banking sectors, ICT sector has shown steady rates of employment. Women employees also take advantage of the positive characteristics of the ICT sector.

Although the population employed in this sector accounts for 4% of total employment, it expects a positive growth in the future which opens new avenues to qualified professionals [START_REF]Encouraging STEM Studies for the Labour Market´[END_REF]. This prospect should encourage young women to seek this educational qualifications and vocational training required by the ICT sector. The higher education and the labor market should adapt their structures in order to attract more young women into this traditionally male environment and encourage them to develop stimulating careers in this sector. Data suggests that encouraging women to enter technological vocations depends on employment policies to reverse the segregation in the labor market and create women friendlier workplaces [13]. Although employment conditions include a great number of work-life balance measures, the opinions of women in the Labor Force Survey suggest it still a stressful context for women workers. This impediment is naïve because this is the most innovative sector, with total flexibility and creativity as fundamental pillars of working hours. The challenge of the ICT sector will be to implement effective measures to adapt its environment to meet the needs of women, relaxing daily work life in the institutions.

Overqualification points to the persistence of gender bias and discriminatory situations in the ICT labor market. It points to fighting against employers (headhunters and other human resources recruiters) and its prejudices related to gender and age. Our suggestion entails training courses for reinforcing abilities and competences in young people. Mentoring programs seem very positive for creating a culture of confidence in the companies and from bosses to young workers. Moreover, mentoring programs are more effective if there is a transfer from business experience to higher school curricula, in order to bridge the gap between learning and professional experience. Working jointly together, from private to public spaces, benefits global competitiveness.

The management of working hours in the workplace is a main factor that contributes to difference between men and women. Women prefer to work shorter hours which suggests that they suffer an increasing pressure on their careers. Care responsibility is a well-known cause of delaying careers for women in the labor market, but we suggest that we should consider other factors related to less stressful conceptions about life and health. The gender gap comes not only from personal choices but also from the dynamics of business world. In our view, companies should deal with a different concept of working-time to attract female and talent. Women accept fewer working-hours, even if they receive lower wages, while men feel this need to a lesser extent. These differences between men and women create asymmetries even where there are gender sensitive policies.

Diversity policy is considered an opportunity to create new perspectives and solutions in the ICT sector. Some international corporations implement diverse models of management for attracting talent concerning the attraction of diverse people (according to their origin, sexual orientation, religion, culture, gender and other characteristics). However, the effectiveness of these policies depend on the cultural change rather than the simple incorporation of people. Diverse talent entails the decision of accepting a different kind of knowledge that inspires creativity and innovation. Classical structures in companies, concerning on-site orientation and rigid hours, could reach its limit. By contrast, the organization of culture tends to erase differences between male and female workers (or diversity of employees) because of a strong tendency to respect the aims of the corporation.

Table 1 .

 1 Rates of employment in ICT sector by age groups

		Men	Women	Total
	25-30	3.9%	1.4%	2.6%
	31-45	5.3%	2.0%	3.7%
	46-64	2.8%	0.6%	1.7%
	Total	3.6%	1.1%	2.4%
		Source: EPA 2015, INE second term

Table 2 .

 2 Gender differences regarding employment typology Source: EPA 2015, INE second term

Table 3

 3

	displays a greater gender

This work was supported by the projects: GENTALENT, 2014ACUP00013, ACUP (Association of Catalan Public Universities) and La Caixa Foundation, GENCPOLIS CSO2014-55556-P, and CIEDES CSO2011-30179-C02-01.


Jane Besong

Sous La

Thierry Michon

Kristiina Mäkinen

Soutenue Le 14

M Teeri Teemu

Professeur Mme Wege Christina

M Hytonen Vesa

M Taliansky

Mme Mäkinen Kristiina

M Michon

MOLECULAR INSIGHTS INTO A PUTATIVE POTYVIRUS RNA ENCAPSIDATION PATHWAY AND POTYVIRUS PARTICLES AS ENZYME NANO-CARRIERS

Molecular insights into a putative potyvirus RNA encapsidation pathway and potyvirus particles as enzyme nano-carriers

The second part of this work entailed the investigation of novel approaches for organizing biocatalysts on virus platforms. The aim was to control the display of enzymes on virus surfaces while maximizing channelling of reaction intermediates. Three strategies were tested but only one involving an antibody binding peptide, the z33 peptide from Staphylococcus aureus was successful. An 87 % occupancy of accessible sites on the potyvirus particles by the enzyme was achieved. The same strategy was used to graft potyvirus particles with two enzymes: 4-coumarate:coenzyme A ligase (4CL2) and stilbene synthase (STS), catalysing consecutive steps in resveratrol synthetic pathway or a protein chimera, generated by the genetic fusion of both enzymes. This was achieved by trapping either the monoenzymes or the protein chimera from clarified soluble E. coli cell lysates on to the surface of potyvirus particles preimmobilized in a polypropylene tube. Resveratrol was synthesized from both mono-enzymes and the protein chimera in solution and on potyvirus particles. This strategy brings together a bottom-up and top down approach for designing virus based nano-materials and offers a cost effective and efficient way to co-immobilize and purify enzymes.

  Keywords nano-carriers, enzymes, encapsidation, immobilisation, nano-technology, virus particles III Unité de recherche Division of Microbiology and Biotechnology Department of Food and Environmental Sciences Faculty of Agriculture and Forestry P.O. Box 56 (Viikinkaari 1) FI -00014 University of Helsinki Finland Equipe de Virologie UMR 1332 Biologie du Fruit et Pathologie INRA et Université de Bordeaux CS

Molecular insights into a putative RNA encapsidation pathway and potyvirus particles as enzyme nano-carriers Résumé

	La présente étude avait pour but d'identifier	trans et en cis et permettant très
	de nouvelles stratégies pour la présentation	probablement le recrutement spécifique de
	sélective d'enzymes à la surface de	l'ARN potyviral pour son encapsidation. En
		accord avec les études d'assemblage in vitro
	application potentielle dans la technologie	publiées précédemment nous proposons un
	des biocapteurs ou des puces à protéines.
	Les potyvirus ont été choisis comme nano-	l'ARN viral est initiée par des interactions
	supports modèles. Les Potyvirus, le genre le	CP-CP co-traductionnelles. Dans la
	plus large de la famille des Potyviridae, la	deuxième partie de ce travail, différentes
	seconde plus grande famille de virus de	approches ont été
	plante, sont responsables de très graves	des enzymes sur les platesformes virales
	pertes dans les cultures. Ils forment des
	capsides flexibles en forme de bâtonnet
	entourant une seule molécule d'ARN positif
	simple brin. Les événements moléculaires
	conduisant à la sélection et à l'encapsidation
	spécifiques de l'ARN potyviral sont
	inconnus. Afin de mieux exploiter le
	potentiel de ces virus comme nano-
	supports, la première étape de ce travail a				pour
		piéger deux enzymes, la 4-coumarate:
	d'encapsidation de l'ARN de particules de	coenzyme A ligase (4Cl2) et stilbène
	potyvirus. Des études précédentes ont	synthase (STS), catalysant des étapes
	montré que la protéine d'enveloppe (CP) du	consécutives dans la voie de synthèse de
	virus de la pomme de terre A (PVA)	resvératrol à partir de lysats cellulaires
	interfère avec la traduction de l'ARN viral
	lorsqu'elle est fournie en excès en trans	particules de potyvirus immobilisées sur les
	suggérant que cela pourrait se produire pour	parois d'un tube en polypropylène. Cette
		stratégie	rassemble	les	approches
	cette étude, nous avons montré que cette	ascendante et descendante pour construire
	inhibition est médiée par des interactions	des nanomatériaux à base de virus et offre
	CP-CP co-traductionnelles se produisant	un moyen efficace et économique pour co-
	entre deux populations de CP, produites en	immobiliser et purifier des enzymes
	Mots clés
	nano-supports, enzymes, encapsidation, immobilisation, nano-technologie, particules virales
	II

intermédiaires réactionnels. Parmi les trois stratégies testées seule celle utilisant un peptide qui se liant aux anticorps, le peptide z33 de la protéine A de Staphylococcus aureus a été couronnée de succès. Une couverture de 87 % des sites sur les particules de potyvirus avec l'enzyme a été obtenue. Cette stratégie a été utilisée

Molecular insights into a putative RNA encapsidation pathway and potyvirus particles as enzyme nano-carriers Abstract

	The present study intended to identify new	viral RNA for encapsidation. In line with
	strategies for the selective presentation of	previously published in vitro assembly
	biocatalysts on the surface of viral	studies, we propose a mechanism through
	nanoparticles with potential application in	which viral RNA encapsidation is initiated
	biosensor technology or protein chips.	through	co-translational	CP-CP
	Potyviruses were chosen as model	interactions.
	nanoscaffolds for biocatalysts. Potyviruses
	are the largest genus in the family
	Potyviridae and cause significant plant
	damage. They form flexible rod-shaped
	capsids surrounding a single stranded
	positive sense RNA molecule. The
	molecular events leading to the specific
	selection and encapsidation of potyviral
	RNA are unknown. To better exploit the
	potential of these viruses as nanocarriers,
	the first step in this study was to look into
	their in vivo RNA encapsidation process.
	Earlier studies showed that Potato virus A
	(PVA) coat protein (CP) interferes with
	viral RNA translation when provided in
	excess in trans and it was suggested this
	could occur to initiate viral RNA
	encapsidation. In this follow up study, we
	used the agroinfiltration approach for the
	transient expression of full length, truncated
	or mutated viral RNAs with wild type CP
	(CPwt) and showed that this inhibition is
	mediated by co-translational CPCP
	interactions occurring between two CP
	populations, produced in trans and in cis.
	Because CP inhibited translation of the
	entire viral genome and virus particles were
	formed later than during normal infection, it
	was assumed that the CP acted during this
	inhibition process to specifically recruit

ACKNOWLEDGEMENTS REFERENCES

LIST OF ORIGINAL PUBLICATIONS

This thesis is based on the following original publications, referred to by their roman numerals throughout the text.

I.

Pille J, Cardinale D, Carette N, Di Primo

UTION I.

Jane Besong-Ndika participated in the research work, analysis and data interpretation.

II.

Jane Besong-Ndika designed and executed most of the experimental work with the exception of RNA gel shift experiments. She analysed the results and interpreted the results with co-authors. JBN wrote the first draft of the manuscript.

III.

Jane Besong-Ndika designed and executed most of the experiments except for the MS analysis. She interpreted the results together with co-authors and wrote the first draft of the manuscript.

Unpublished data is also presented which showcase the work JBN carried out to identify a successful strategy to graft functional biological molecules on potyvirus scaffolds.


Ali Saad

Charles-André Gandin
email: charles-andre.gandin@mines-paristech.fr

Michel Bellet

Temperature-based energy solver coupled with tabulated thermodynamic properties -Application to the prediction of macrosegregation in multicomponent alloys

Keywords: Finite element method, energy conservation, thermodynamics, solidification, macrosegregation

We present a new algorithm for solving energy balance in phase change problems, particularly in solidification with macrosegregation. The algorithm is based on a nonlinear temperature evaluation using the average enthalpy which is provided by i) tabulated phase transformation paths and ii) tabulated phase properties. The compatibility of this method with tabulations using a thermodynamic database, allows simulating solidification at equilibrium with multiple phase transformations for binary and multicomponent alloys. The method has been validated and applied to three-dimensional cases with macrosegregation: a binary Sn -3 wt.% Pb alloy and a ternary Fe -2 wt.% C -30 wt.% Cr alloy. For the latter case, predictions include composition maps for C and Cr due to thermosolutal instability leading to freckle formation and the subsequent distributions of liquid, BCC, FCC, M 7 C 3 and Cementite phases. Compared with a previously published enthalpy method, the temperature-based energy solver shows similar accuracy and faster computational time.

Introduction

Macrosegregation, a well distinguished defect in alloy solidification, has been a main research topic in the metallurgy community for the last few decades [START_REF] Beckermann | Modelling of macrosegregation: applications and future needs[END_REF]. It develops within several physical scales: at a microscopic scale, solute partitioning between the liquid and solid phases creates composition gradients at the interface between the phases, known as microsegregation [START_REF] Dantzig | Solidification[END_REF]. Macroscopically, fluid flow in the liquid phase as well as other mechanical factors, such as deformation of the mush [START_REF] Lesoult | Segregation during solidification with spongy deformation of the mushy zone[END_REF], [START_REF] Lesoult | Erratum to "Segregation during solidification with spongy deformation of the mushy zone[END_REF], solidification shrinkage [START_REF] Flemings | Macrosegregation: Part I[END_REF] and transport of grains [START_REF] Založnik | An operator splitting scheme for coupling macroscopic transport and grain growth in a two-phase multiscale solidification model: Part I -Model and solution scheme[END_REF], [START_REF] Založnik | An operator splitting scheme for coupling macroscopic transport and grain growth in a two-phase multiscale solidification model: Part II -Application of the model[END_REF] may redistribute unevenly the rejected chemical species. These transport phenomena gradually enrich or deplete the melt located outside an established mushy zone, leading to regions with significant composition differences, hence altering the properties in the finished product. To model macrosegregation, a minimum of four conservation principles are used: conservation of mass, momentum, chemical species and energy. The phase change literature contains a wealth of numerical methods to solve energy conservation in solidifying alloys. A comprehensive overview of these methods is given by Swaminathan and Voller [START_REF] Swaminathan | On The Enthalpy Method[END_REF]. The corresponding equation associates the total average enthalpy to the temperature via intrinsic alloy properties, such as the heat capacity of the phases and the latent heat associated with the phase transformations. However, in the course of solidification with macrosegregation, these properties may change because the average composition may vary significantly: the transformation paths are then modified, as well as the phases" composition and heat capacity. Similarly, the latent heat of phase transformations is not a constant that could be distributed as a function of the phase fractions assuming only temperature-dependent phases" properties, as often found in the literature [START_REF] Bellet | Call for contributions to a numerical benchmark problem for 2D columnar solidification of binary alloys[END_REF]. It is thus impossible to establish a priori the dependence of the enthalpy with respect to temperature when macrosegregation takes place, even in the case of full thermodynamic equilibrium between phases. The current work discusses a suitable numerical scheme based on an enthalpy method, already used in the literature to alleviate this macrosegregation-related problem [START_REF] Swaminathan | On The Enthalpy Method[END_REF], [START_REF] Carozzani | Direct Simulation of a Solidification Benchmark Experiment[END_REF]. Secondly, we introduce a modified formulation, using the effective heat capacity method that increases the original scheme"s efficiency. The current method is thus an enthalpy method that makes use of a temperature-based solver. Moreover, it uses tabulated thermodynamic quantities (solidification paths, phases" enthalpy and composition) in a range of average compositions and temperatures as found in the literature [START_REF] Doré | Modelling of microsegregation in ternary alloys: Application to the solidification of Al-Mg-Si[END_REF]- [START_REF] Thuinet | Prediction of macrosegregation during the solidification involving a peritectic transformation for multicomponent steels[END_REF], with the aim of evaluating the total average enthalpy as well as the effective heat capacity. The novelty of the modified method resides in the use of thermodynamic tabulations without losing the advantages of the previous method, thus yielding faster computation times while maintaining a good accuracy. Finally, test cases are presented.

Thermodynamic Considerations

Volume averaging

A volume averaging technique was suggested to deal with the presence of multiple phases [START_REF] Ni | A volume-averaged two-phase model for transport phenomena during solidification[END_REF]. It locally considers a Representative Volume Element (RVE) that contains several phases at a mesoscopic scale. We represent, for each unknown , an intrinsic volume average, (also denoted in the literature), corresponding to a phase . The volume average for this unknown in the RVE, hence averaged over all the present phases writes:

Eq. 1 where denotes the volume fraction of phase in the RVE. It should be emphasized that the averaging technique applies to virtually all thermodynamic variables (enthalpy, density …). Among these variables, the temperature is considered to be uniform in the RVE. Applying the volume averaging technique to the energy conservation principle along with interfacial balances between the phases, results in the following averaged equation [START_REF] Rappaz | Numerical Modeling in Materials Science and Engineering[END_REF]:

Eq. 2
where stands for the density, the mass enthalpy, the velocity field, the thermal conductivity, the temperature and a possible volume heat source. While the latter source is zero in the rest of this contribution, we keep it to maintain a general formulation of the energy conservation. Eq. 2 is the standard averaged form of the energy conservation equation used in non-stationary phase change problems. Once the variational form has been discretized in space and time, two possible resolution schemes emerge: the first is an explicit forward Euler scheme which gives rise to a linear equation where the temperature denoted by is known at time t. This requires very small time steps in the current context, which limits the solver"s usability at the scale of industrial applications. The second scheme is the backward Euler or full implicit discretization where terms are function of . It leads to a nonlinear equation with 2 interdependent unknowns, and . It is clear that the nature of the temperature-enthalpy relationship plays a central role when formulating the resolution strategy of this nonlinear equation. Generally, it is admitted that, depending on the resolution strategy, it is necessary to express enthalpy as a function of temperature or vice-versa, together with associated partial derivatives, or .

The temperature-enthalpy relationship

In solidification problems, additional variables are involved in Eq. 1 and Eq. 2, like the transformation path that defines the history of the phase fractions, as well as the average chemical composition , being the index of the chemical species (only the solutes are considered). The temperature-enthalpy relation averaged over the phases in a given RVE writes:

Eq. 3
Note that the volume average enthalpy is approximated by the product in the current work. As stated in the introduction, it becomes clear from Eq. 3 that phase properties, i.e. average phase density, , and enthalpy, , are temperature and composition dependent. This equation is the key to convert the average volume enthalpy to temperature (through a procedure named H2T) or vice-versa (T2H). The values of the different phase fractions (solidification path) and phase enthalpies are thus needed to close the relation.

Tabulation of properties

The complexity of performing a thermodynamic conversion is directly linked to the simplicity of determining the alloy properties, namely the phase fractions and phase enthalpies. In the case of binary alloys and with several assumptions with respect to the system (e.g., linear monovariant temperature-composition relationships, constant heat capacity of phases and constant latent heat of transformations, equilibrium approximations between phases) analytical calculations are often used to determine the properties. Nevertheless, analytical relations are more complex or even impossible to derive in the case of multicomponent alloys ( ). To overcome this problem, one can resort to thermodynamic databases and phase equilibrium calculations to tabulate the transformation paths and the phase enthalpies for a given range of temperatures and average compositions. It is a handy solution for two main reasons: first, the conversion is merely a binary search in a table; secondly, it is a simple solution for coupling with macrosegregation. In this way, phase fractions are tabulated as functions of temperature and average composition, while for each phase the mass enthalpy, , and the density, , are tabulated as functions of temperature and phase intrinsic average compositions , as well as other possible parameters. Figure 1 summarizes the steps in order to perform a temperature-to-enthalpy (T2H) conversion using the predefined tabulation approach. In step 1, the transformation path is acquired for each average composition and temperature to determine the list of phases, their volume fractions and their intrinsic compositions . In step 2, the phase enthalpy and density are determined by searching for the temperature and the already known phase composition . In step 3, the average volume enthalpy is computed from the volume fraction, density and mass enthalpy of phases using Eq. 3.

Step The methodology to build the tabulations is straightforward. It is based on two main scans. On the one hand, intervals for the variation of the average composition are chosen from the known alloy composition. These variations have to cover the extreme values adopted during the simulation, which are not known a priori. An interval is also selected for the variation of temperature. The latter is easier to determine as it usually starts from the initial melt temperature and goes down to the room temperature in a standard casting simulation. For these intervals, a systematic scan is made with chosen steps in each composition and T, during which a thermodynamic equilibrium is computed. The outputs are the number of phases encountered, together with their fraction and intrinsic composition. The minimum and maximum intrinsic composition for each phase could then be determined. On the other hand, for each phase, a scan of the intrinsic composition and temperature is made to compute the intrinsic properties. The same temperature interval and step as defined earlier are used. This strategy based on full thermodynamic equilibrium means that it is limited to the so-called lever rule approximation. Regarding the enthalpy-to-temperature conversion (H2T), a backward iterative T2H search is performed. For a known composition , denoting the iteration index to convert the enthalpy , we start with an initial guess for temperature then convert it to an enthalpy with the T2H conversion. Using an appropriate nonlinear algorithm (Brent is the most versatile in our case), we aim at minimizing the following residual: . Once the algorithm has converged, the temperature is the result of the H2T conversion. It is inferred that the first conversion (T2H) is a direct one whereas the latter (H2T) is indirect and requires a series of iterative steps; each step being a single T2H resolution. In other words, a H2T conversion is a backward search for a temperature, hence it"s slower. This conversion"s speed lag is aggravated when tabulations increase in size (e.g. large number of temperature and composition steps) and complexity (e.g., multicomponent industrial alloys used in casting), since the search gets more complicated with the increasing number of input columns (one column for each alloying element).

Numerical method

The finite element method is used to solve the energy conservation as expressed by Eq. 2. A test function belonging to the Hilbertian Sobolev space of continuous integrable test functions is used to formulate the integral variational form of Eq. 2 [START_REF] Süli | Lecture Notes on Finite Element Methods for Partial Differential Equations[END_REF]. A Fourier boundary condition is considered on the domain boundary . The domain is discretized using first-order linear simplexes defined by their number of local nodes (denoted " "): triangles in 2D with and tetrahedra in 3D with . The outcome is a residual that we aim to minimize so that the conservation principle is satisfied. Assuming a static solid phase and an incompressible liquid phase, it can be shown that the second term of Eq. 2 can be cast into the expression . Therefore, its weak (variational) form is defined as follows:

Eq. 4

The steps for discretizing in time and space the previous equation are detailed in the literature [START_REF] Dantzig | Solidification[END_REF], [START_REF] Rappaz | Numerical Modeling in Materials Science and Engineering[END_REF]. As for enthalpy and temperature, they are spatially discretized in each finite element using interpolations functions , thus defining the nodal values and , respectively:

Eq. 5

Eq. 6

Note that is a volumetric enthalpy. The Galerkin formulation gives the following expression for the residual contribution at a mesh node for time step in a local element : The surface integrals and are related to a Fourier-type boundary condition, with as a coefficient of heat exchange and as the external temperature far from the boundary. The energy conservation principle is satisfied when the sum of the residual contributions coming from all the mesh elements is zero. In other words, the following global residual defined by the assembly of these contributions, should be minimized:

Eq. 8
where the global matrices , ,

, and contain respectively, after an assembly step, the contributions of the local matrices , , , , and from each discretized element in the domain . Accordingly, the indices and refer to global node numbers, where the total number of nodes denoted by . It is clear that the global residual, inherits the dependence between enthalpy and temperature. This is shown in Eq. 8 where the average volume enthalpy is a function of the temperature. It infers that this residual is a non-linear function; therefore minimizing it requires an iterative non-linear algorithm. Our choice settles on the Newton-Raphson method, known for its quadratic convergence speed. A solidification problem can induce severe non-linearities from the release of the latent heat (which itself is temperature-composition dependent) and the variations of the thermophysical properties of the alloy with respect to temperature and average composition. This algorithm could thus treat such variations. Considering the link between enthalpy and temperature, Eq. 8 may be solved either for enthalpy or for temperature as a nodal unknown; hence both formulations are presented hereafter.

Enthalpy-based approach (Hsolver)

The residual is re-written using a Taylor series expansion to the first order for a nonlinear iteration :

Eq. 9

Neglecting the second order terms, the suggested correction at each iteration in view of cancelling the residual and giving the new value , is given by the linear system:

Eq. 10
where is a global tangent matrix yielding the variations of the residual with respect to the enthalpy in the last iteration, . If Eq. 7 is considered, then the contribution of an element writes:

Eq. 11

Eq.11 is the core of the enthalpy-based solver. The resolution of Eq.10 then yields a new estimate of the vector of nodal enthalpies , which are the only unknowns to be solved for. Once determined at iteration , convergence tests are performed as explained in section 3.3.

Temperature-based approach (Tsolver)

Similarly to the Hsolver, the local residual is recast for a nonlinear iteration , leading this time to an iterative temperature correction:

Eq. 12
where is a global tangent matrix yielding the variations of the residual with respect to temperature at the previous iteration. The contribution of an element to this tangent matrix is evaluated as:

Eq. 13

In contrast to the previous solver, Eq. 13 is the core of the temperature-based solver. The resolution of Eq.12 yields a new estimate of the vector of nodal temperatures , which are the only unknowns to be solved for. Once updated for iteration , convergence tests are performed (see next section).

Convergence

The previous two sections described the iterative resolution of the same discretized energy conservation (Eq.4) by Tsolver and Hsolver. However, in both equations 11 and 13, an important term emerges from the tangent matrix evaluation describing the variations between temperature and enthalpy:

(or its inverse). This term invokes the previously mentioned temperature-enthalpy tabulations which depend on the alloy composition. Consequently, (respectively its inverse) has a great influence on the convergence of the Tsolver (respectively the Hsolver). At a nonlinear iteration , this term is written using a finite difference: Tsolver Eq. 14

Hsolver

Eq. [START_REF] Rappaz | Numerical Modeling in Materials Science and Engineering[END_REF] For the Tsolver, the enthalpy is needed to evaluate Eq. 14. In contrast, the Hsolver requires the value of to evaluate the corresponding Eq. 15. In both cases, the unknown is determined by the temperatureenthalpy relation. The indices next to the mentioned unknowns indicate that this relation is used for each iteration at each mesh node , hence affecting the global resolution time between the two solvers. The Hsolver needs a H2T to evaluate , whereas the Tsolver needs a T2H to evaluate . The flowchart in Figure 2 demonstrates the process. It can be seen that Tsolver uses solely T2H procedure and the thermodynamic tabulations to determine the enthalpy, hence the term . On the other hand, Hsolver repeats the same procedure a finite number of times in order to determine a temperature output through H2T and use it to compute . This algorithmic difference leverages the Tsolver in terms of computation time providing the same numerical accuracy while conserving the total system energy. Convergence tests are necessary at the end of each iteration of the energy solver to determine the convergence status of the algorithm. In the context of the Tsolver for instance, the residual is re-evaluated with the newly determined temperature and enthalpy so Eq. 8 rewrites:

Eq. [START_REF] Süli | Lecture Notes on Finite Element Methods for Partial Differential Equations[END_REF] The norm of the current residual, , is compared to a fixed small value . The resulting temperature variation, , has also to verify a similar condition between two consecutive iterations. For that purpose, we compare it to another fixed value .

Convergence is ultimately achieved when the following criteria are simultaneously met:

Eq. 17

A comparison of both solver formulations is done in the hereafter test cases section.

Test cases for binary alloys

Pure diffusion

The two solvers are first tested in a purely diffusive case for a one-dimensional solidification configuration.

Predictions with a 1D front tracking model [START_REF] Gandin | From constrained to unconstrained growth during directional solidification[END_REF] is used as a benchmark. It provides solutions for the temperature and solid fraction during directional solidification of a 10 cm long Al -7 wt.% Si ingot. The melt, with initial uniform temperature, is cooled with a heat exchange coefficient (assuming a Fourier boundary condition) from one side, the other side being adiabatic. All values for alloy properties, initial and boundary conditions and numerical parameters are listed in Table 1. For this simple test case, we use linear temperature dependence of the intrinsic phase enthalpies, that is and , where is the heat capacity per unit volume and is the latent heat per unit volume. Values for and , as well as for the thermal conductivities, = , are taken constant. Moreover, a Gulliver-Scheil approximation is used to compute a single temperaturefraction of solid relationship in the absence of macrosegregation. This is done assuming a linear binary phase diagram and thus requires using the properties listed in Table 1, i.e. the segregation coefficient, k, the liquidus slope, m L , the liquidus temperature, T L , and the eutectic temperature, T E . Figure 3 shows the comparison with the Hsolver and Tsolver. The results are found superimposed to the front tacking solution, thus giving validation of the implementation as well as the iterative schemes presented above to solve the energy conservation. 3 10

Convection-diffusion with macrosegregation

Table 2 presents the additional equations used in a second solidification benchmark with macrosegregation for a simple binary alloy (i=1). For the conservation of energy, Eq.2 is kept. Conservation equations in Table 2 are for mass, momentum and chemical species. As for energy, they are presented after the volume averaging technique has been applied [START_REF] Dantzig | Solidification[END_REF], [START_REF] Ni | A volume-averaged two-phase model for transport phenomena during solidification[END_REF]. Moreover, an assumption of a static and non-deformable solid phase is made. Consequently, the mechanical model is reduced to the conservation of momentum in the liquid phase. This assumption also yields some other consequences on the mass balance and the liquid momentum conservation. In the latter, is the stress deviator tensor in the liquid phase. A Darcy term is added to take into account the dissipative interfacial stress in the porous-like mushy zone. Its main parameter is the permeability of the mushy zone, K. It is considered isotropic, hence reducing to a scalar which is given by the Carman-Kozeny relation, based on the secondary dendrite arm spacing :

. The liquid density being taken constant, its spatial variations as a function of temperature and average composition are still needed to compute thermosolutal convection forces. For that purpose, the Boussinesq approximation is used, considering the thermal and solutal expansion coefficients and a reference density, , defined at a reference temperature and reference composition . Values for the references are taken at the liquidus temperature and the nominal composition of the alloy, [START_REF] Carozzani | Direct Simulation of a Solidification Benchmark Experiment[END_REF]. More details about the FE formulation can be found in [START_REF] Rivaux | Simulation 3D éléments finis des macroségrégations en peau induites par déformations thermomécaniques lors de la solidification d"alliages métalliques[END_REF], [START_REF] Carozzani | Développement d"un modèle 3D Automate Cellulaire-Éléments Finis (CAFE) parallèle pour la prédiction de structures de grains lors de la solidification d"alliages métalliques[END_REF]. Also note that the macroscopic solute diffusion coefficient in the solid phase is neglected in Eq. 20.

Figure 3: Computed unidirectional heat diffusion during solidification of an Al -7 wt.% Si alloy using (orange) the enthalpy method and (black) the temperature method, comparison being made for (left) cooling curves and (right) time history of the liquid fraction. Each curve corresponds to a position along the sample, from 0 cm (cooling side) to 10 cm (insulated side), with 2 cm spacing between the positions.

Mass

Eq. 18

Momentum

Eq. [START_REF] Carozzani | Développement d"un modèle 3D Automate Cellulaire-Éléments Finis (CAFE) parallèle pour la prédiction de structures de grains lors de la solidification d"alliages métalliques[END_REF]

Chemical species

Eq. 20 Table 2: Averaged conservation equations for the conservation of mass, momentum and solute mass

The Tsolver"s ability to be coupled with various physical phenomena like macrosegregation and fluid flow in porous medium is displayed in this test case. It consists of a solidification benchmark where a 10 cm width × 6 cm height × 1 cm thick cavity containing a Sn -3 wt.% Pb melt is cooled down from its two narrowest vertical sides using heat exchangers (LHE: left heat exchanger, RHE: right heat exchanger). The experiment, inspired by Hebditch and Hunt"s [START_REF] Hebditch | Observations of ingot macrosegregation on model systems[END_REF] similar set up, has been revisited by Hachani et al. [START_REF] Hachani | Experimental analysis of the solidification of Sn-3 wt.%Pb alloy under natural convection[END_REF] who performed the solidification with better controlled conditions and using an increased number of samples for composition analysis. Recently, a successful attempt to simulate the experiment was carried out by Carozzani et al. relying on an enthalpy resolution [START_REF] Carozzani | Direct Simulation of a Solidification Benchmark Experiment[END_REF]. All details regarding geometry, finite element discretization, material properties and boundary conditions can be found in the latter reference. For this computation, solidification paths, phase compositions and phase enthalpies were determined by a thermodynamic module dedicated to equilibrium calculations for binary alloys. The 3D simulation results in Figure 4 show a satisfactory agreement with the experimental temperature measurements recorded at mid-heights of the cavity and uniformly distributed along its width [START_REF] Carozzani | Direct Simulation of a Solidification Benchmark Experiment[END_REF]. In fact, simulation results with the Tsolver and the Hsolver were found to be almost superimposed, as in Figure 4. Regarding the computation, the Tsolver resolution proves to be faster than the Hsolver used in [START_REF] Beckermann | Modelling of macrosegregation: applications and future needs[END_REF]: a process time of 7000s required a computation time of 90 hours 13 minutes compared to 114 hours 21 minutes spent by the enthalpy resolution with 32 cores on the same cluster. The gain factor is about 20%.

Casting of a multicomponent alloy

The efficiency of the temperature-based resolution resides in its performance when combined with thermodynamic tabulations. A multicomponent alloy consists of at least two solute elements, and therefore the tabulation size increases, hence the number of search operations also increases. To demonstrate the speed-up ability of the temperature-based approach while predicting all phase transformations during macrosegregation, we consider the solidification of a ternary alloy, Fe -2 wt.% C -30 wt.% Cr. As illustrated in Figure 5a, the alloy domain has a cylinder shape close to 3 inches height × 1 inch diameter. Exact values are reported in Table 3 with all material properties, initial and boundary conditions, as well as numerical parameters for the simulations. The melt steel is initially at 1395°C. The temperature of the bottom surface is imposed with a constant decreasing rate of 0.1 K.s -1 starting with 1380 °C, i.e. 40°C higher than the nominal liquidus temperature, as shown in Figure 5b. The other surfaces are kept adiabatic. The cylinder is held in a vertical position. In these conditions, and knowing that the carbon and chromium solutes have lightening effects on the liquid at nominal composition, the density inversion resulting from the composition gradient in the interdendritic liquid, may cause flow instability (segregation plumes) at the solidification front. While the selected alloy is a steel, this application is also representative of directional cooling in a single crystal casting, e.g. for nickel-base superalloys [START_REF] Beckermann | Development of a freckle predictor via rayleigh number method for single-crystal nickel-base superalloy castings[END_REF]. Figure 5c also provides the transformation path of the alloy at nominal composition, i.e. assuming no macrosegregation and full thermodynamic equilibrium as computed with ThermoCalc and the TCFE6 database [START_REF] Andersson | Thermo-Calc and DICTRA[END_REF], [START_REF]TCFE6: a thermodynamic database for different kinds of steels and Fe-based alloys[END_REF]. A total of 5 phases need to be handled, the characteristic temperature for their formation being reported in Figure 5b.

Thermodynamic tabulations

Full thermodynamic equilibrium is considered in the present case. Due to macrosegregation, the average composition is expected to continuously vary in time and space during casting. Transformation paths are thus determined a priori for a set of average compositions around the nominal value. Hence, carbon content is arbitrarily varied in the interval [1.8wt.%, 2.2wt.%] while chromium content variation is in the interval [27wt%, 33 wt%]. The offset of ±10% with respect to the nominal composition value allows tabulating relatively small composition steps to ensure a fairly accurate mapping when compared to the corresponding ternary phase diagram. The average composition step is 0.04wt.% for carbon and 0.6 wt.% for chromium, thus representing 2% intervals with respect to the nominal composition. The temperature varies in the interval [100°C, 1600°C] by 5°C steps. For each triplet (carbon content in wt.% C, chromium content in wt.% Cr, temperature T in K) corresponds a phase fraction and a pair of intrinsic phase composition . For the 5 phases listed in Figure 5c (LIQ≡liquid, BCC≡ferrite, FCC≡austenite, M7C3≡carbide, CEM=cementite), the enthalpy and density , are tabulated as functions of temperature and phase intrinsic composition. If this latter input lies between two tabulated values, a linear interpolation is performed to determine the output, i.e. phase enthalpy and density. With the advancement of solidification, the liquid is enriched with solute by macrosegregation, which enables new solidification paths. It means that the primary solidifying phase is not necessarily the same as when considering the nominal composition. For this reason, the tabulation approach is interesting inasmuch as it provides phase transformation paths and values of phase properties that are compatible with the system"s actual composition. Figure 6 summarizes the tabulated thermodynamic data for two sets of average composition for the considered ternary system. Note that in the present test case, phase densities are taken constant ( kg.m -3 ). Therefore they are not tabulated. With this assumption, no shrinkage occurs upon phase change.

Solidification without macrosegregation

A first case is considered without macrosegregation, that is, all mechanical driving forces are bypassed, leading to a static melt. This is achieved by nullifying the thermal and solutal expansion coefficients, which is equivalent to a constant density in space and time, i.e. no Boussinesq force is considered. This way, the average composition may only vary due to diffusion in the liquid phase according to Eq. 20 where the convection term is neglected. Diffusion is significantly small in the present case and can be neglected too.

In such a case, the composition distribution maintains a homogeneous aspect throughout the sample during the entire cooling sequence. The phase transformations then are necessarily expected to follow the unique path shown in Figure 5c. After 407 s of cooling, the liquidus isotherm enters the bottom surface of the geometry and starts its upward propagation, marking the solidification onset. Figure 7 presents the simulation results at 3 successive times for the distribution of the solute species and the temperature, as well as for the fraction of phases listed in Figure 5c. At 600 s, a fully liquid region is still largely present while the mushy zone is made of liquid plus the primary solid phase (ferrite). At 10560 s, the sample is full solid, with fractions of ferrite and cementite that corresponds to the values read in Figure 5c at low temperature. At the selected intermediate time, the presence of 4 phases is found. The solid region at the bottom of the cylinder is made of ferrite, austenite plus carbide, the temperature being still too high to permit the cementite to form. The mushy zone above the solid region is characterized by the presence of 3 phases due to a peritectic reaction taking place that progressively transform ferrite into austenite in the presence of liquid. It can be noticed that the phase fraction isovalues in Figure 7 (at 600 s) are horizontal, owing this to two factors: the first is the temperature field, which varies unidirectionally from bottom to top, controlled by thermal diffusion, while the second is the uniform average composition throughout the sample due to the absence of convection. In fact both factors are consequences of the flow absence, which would transport heat and solute by advection, thus inevitably changing the phase distribution. The succeeding phase change is a solid-state transformation where -ferrite and the carbide M 7 C 3 react to form cementite at 490°C at nominal composition, as shown in Figure 5b. The reaction is relatively slow, ending with 28% of cementite and 72% of -ferrite.

Solidification with macrosegregation

In this case, the artificial consideration of a still flow is dropped, hence taking into account macrosegregation caused by the fluid motion by using realistic values of the expansion coefficient given in Table 3. Solidification starts at 407 seconds when the cylinder"s bottom base temperature reaches the liquidus temperature of the alloy. In fact, the solidification onset is the same as in the former case, since the average composition remains unchanged for an entirely liquid domain (assuming an initially infinite solute mixing in the melt). As shown in Figure 8 at 600 s, the first solid phase to form remains ferrite. We can also see solute-rich channels forming in the mushy zone and solute plumes rising in the melt above the mushy zone due to a subsequent upward flow. It is actually caused by the thermosolutal buoyancy force created by the carbon and chromium solutes. Such phenomenon could delay solidification inside liquid-rich channels and results in a freckling defect [START_REF] Felicelli | Simulation of freckles during vertical solidification of binary alloys[END_REF] on the surface of the cylinder as well as inside, as shown later in this section. As solidification proceeds, the liquid becomes more enriched with solute and the peritectic reaction forming the austenite phase is reached. However, for very large enriched melt, it can also be observed that primary solidification proceeds with the austenite phase rather than the ferrite phase. The carbide phase can also form with the austenite phase at some locations. These observations correspond to a simulation time of 2000 s in Figure 8. Solidification ends at around 2475 s, the last liquid solidifying at the cylinder"s top surface, where the average composition reaches a maximum of Fe -2.151 wt.% C -30.633 wt.% Cr, i.e. a relative positive macrosegregation, , of 7.5% for carbon and 2.1% for chromium. The fact that the maximum average composition is observed at the top, is verified in Figure 9a which shows the composition map in a 2D vertical slice through the longitudinal axis of the cylinder. We can also see it in Figure 9b where the relative composition profile are plotted at the end of the cooling process along the longitudinal cylinder axis Z-Z" and along the axis of the freckle, F-F". The negative segregation up to 1 cm from the chill corresponds to the solute depletion caused by the first solid formation. The subsequent solidification enriches further the liquid; hence the solid composition also increases. The composition evolution trend for both solutes is similar: an overall rise until positive segregation is achieved above 5 cm from the chill. The positive macrosegregation intensifies when the profile is chosen at the center of the freckle, negative segregation then becoming less pronounced. Beyond 2475 seconds, no variations of the average composition maps are observed since solute diffusion in the solid phases is neglected. Nonetheless, as temperature decreases, solid-state transformations are still possible as for the case with no macrosegregation. The formation of a cementite phase begins at the cylinder base at 8843 s with a temperature of 496.9°C. At about 9293 s, the isotherm 488.5°C reaches the top surface. This temperature value is the local cementite solvus temperature. The difference in the solvus temperature between the bottom and top surfaces is due macrosegregation. Macrosegregation also explains the variation in the cementite content. The solid state transformation ends shortly before 10500 s. The final phase distribution is clearly dependent on the final macrosegregation pattern. They retain the shape of the freckles that were caused by thermosolutal convection, hence demonstrating the heritage of the solidification process on the final distribution of phases. This is better illustrated by drawing the time evolution of the fraction of phases at the center of the bottom and top surfaces of the cylinder in Figure 10. With no macrosegregation, in Figure 10a, the final distribution of the phases is the same at time 12000 s, while with macrosegregation, in Figure 10b, variations of the cementite and ferrite are revealed. The previously mentioned segregation plumes have transformed to freckles, inside the cylinder and on the boundary. This defect is marked by a noticeable gradient of composition and phase fractions, possibly changing the mechanical properties in the channels, hence the overall mechanical behavior of the alloy [START_REF] Copley | The origin of freckles in unidirectionally solidified castings[END_REF].

The coupling of the Tsolver with thermodynamic tabulations is thus demonstrated. It shows the ability to predict complex solidification paths, even if only at equilibrium. As for the computation time, the Tsolver resolution performed better: 500 seconds of solidification required 6 hours 14 minutes compared to 8 hours 6 minutes spent by the enthalpy resolution with 12 cores on the same machine. The gain factor is about 22 %. A new algorithm for solving the energy balance has been presented. It is particularly suited for solidification problems with macrosegregation. Tabulated thermodynamic data makes it possible to predict several solidification paths for a range of average compositions. The algorithm, based on a temperature-stepping resolution, is compared to a classical enthalpy solver with the same tabulated properties for phase fractions, compositions and enthalpies. Validation has been performed with a 1D pure diffusion solidification case, as well as a 3D case with macrosegregation, the alloys being binary in both cases. A demonstration has then been shown with an iron-carbon-chromium ternary alloy. The temperature-based method proved to be faster in computation time in all cases. Coupling with the prediction of grain structure is presently under development [START_REF] Saad | Simulation of Freckle Formation in Directionally Solidified In -75 wt.% Ga -Qualitative Comparison with In Situ Observations[END_REF], considering the importance already demonstrated elsewhere [START_REF] Carozzani | Direct Simulation of a Solidification Benchmark Experiment[END_REF], [START_REF] Gandin | From constrained to unconstrained growth during directional solidification[END_REF]. Besides, this article only presents tabulations used with the approximation of full equilibrium -or lever rule-for macrosegregation calculations. Only for the test case considering pure diffusion in Al-7wt%Si the Gulliver-Scheil path was considered. For this particular alloy, there is little difference between these two paths. And in case of macrosegregation in binary systems such as SnPb and PbSn alloys, literature shows that little difference is found [START_REF] Ahmad | Numerical simulation of macrosegregation: a comparison between finite volume method and finite element method predictions and a confrontation with experiments[END_REF]. It is clear however that this approximation remains limiting for multicomponent alloys. For steels, a third type of approximation is even required, named partial equilibrium, that considers equal chemical potential of interstitial elements in all phases (e.g., C), while substitutional species in the solid phases (e.g., Cr) are frozen [START_REF] Koshikawa | Computation of Phase Transformation Paths in Steels by a Combination of the Partial-and Para-equilibrium Thermodynamic Approximations[END_REF].

Figure 1 :

 1 Figure 1: Tabulation processing for a T2H procedure

Figure 2 :

 2 Figure 2: Flowcharts showing the steps to compute the nonlinear terms using tabulations

Figure 4 :

 4 Figure 4: Experimental cooling curves overlap with the results of the 3D FE simulation. The left (LHE) and right (RHE) heat exchangers impose the boundary temperature in the experiment

Figure 5 :

 5 Figure 5: Configurations for directional casting of (a) a 1 inch diameter × 3 inches height cylindrical domain for which (b) temperature-time conditions are imposed at its bottom surface. The alloy is Fe -2 wt.% C -30 wt.% Cr, its computed transformation path [23], [24] at nominal composition being displayed in (c).

Table 3 :

 3 Parameters for solidification of alloy Fe -2 wt.% C -30 wt.% Cr presented in Figure 5 -10

Figure 6 :

 6 Figure 6: Tabulated thermodynamic data for the ternary system Fe-C-Cr alloy with software Thermo-Calc [23] with database TCFE6 [24]

Figure 7 :Figure 8 :

 78 Figure 7: Upward solidification of a cylinder rod with a static liquid at 3 stages in a Fe -2 wt% C -30 wt% Cr alloy. The left columns show the average composition and temperature distribution, while the right columns show the phase fractions

Figure 10 :Figure 9 :

 109 Figure 10: History of phase fraction (a) without macrosegregation and (b) with macrosegregation at the center of the (plain) bottom and (dashed) top surfaces of the cylinder surfaces, extracted from simulation displayed in (a) Figure 7 and (b) Figure 8

Table 1 : Parameters for the pure diffusion test case with alloy Al -7 wt.% Si presented in Figure

 1

	Parameter	Symbol	Value	Unit
	Nominal composition		7	wt.%
	Liquidus temperature	T L	618	°C
	Eutectic temperature	T E	577	°C
	Segregation coefficient	k	0.13	wt.% / wt.%
	Liquidus slope	m L	-6.5	wt.% °C-1
	Heat capacity (liquid and solid)		2.6 •10 6	J m -3 °C-1
	Enthalpy of fusion	L	9.5 •10 8	J m -3
	Thermal conductivity (liquid and solid)		70	W m -1 °C-1
	Heat transfer coefficient		500	W m -2 °C-1
	External temperature		100	°C
	Initial temperature	T 0	800	°C
	Ingot length		0.1	m
	FE mesh size		10 -3	m
	Time step		0.1	s
	Convergence criterion (residual) Convergence criterion (temperature)	 R  T	10 -6 10 -2	-K

Acknowledgements

This work was funded by the European Space Agency under the projects CCEMLCC (grant AO-2004-017) and NEQUISOL (grant AO-1999-023) aiming to study containerless solidification of alloys in microgravity conditions.


Céline Bourbousson

Inter-organizational collaboration in territorial development projects

Keywords: Inter-organizational collaboration, territory, bottom-up, boundary object, regulation

This paper is derived from the ambition to analyze inter-organizational collaboration in so-called bottom-up projects. These projects have the particularity to be conducted by extremely diverse groups of actors, and the theory of boundary object lends itself very well to their comprehension. However, it doesn't allow to consider the different levels of context that impact the projects. We propose to combine it with a regulation approach, in order to take into account the meso and macro articulations and constraints. We proceed by a comparative and multilevel case study of : 1/ a French cluster in the field of eco construction (PTCE), 2/ an emerging Natural Park in Mexico. Our findings overcome monocausal explanations and provide insights in the contradictions between the local institutional arrangements of the projects and the meso and macro institutional mechanisms.

INTRODUCTION

Public policy elaboration, influenced by the recent evolutions of theoretical fields such as human geography, management or territorial economy refers more and more to the concept of bottom-up projects. Top down projects have been charged with being both too much driven by public institutions and out of touch with reality. Bottom-up initiatives have been conversely valued for their supposed local and participative property. In other words, this kind of territorial development projects has been conceived as a way to efficiently fulfill local needs by using a participative approach.Such initiatives are conducted by extremely diverse groups of actors -institutional actors, activists, scholars, NPOs -and have the particularity to require collaboration of different social worlds. Thus, the actors have to find solutions to deal with heterogeneity. They have to create common understanding and shared meaning. However, in many cases, so-called territorial development projects were initially driven by a public or semi-public structure and hardly ever succeeded in enabling multi-actors collaboration.

In this paper, territorial development projects are analyzed through the theoretical framework of boundary objects (Star, Grisemer, 1989). This theory is useful for understanding the production of common representation and for explaining inter-organizational collaboration (IOC). Yet, it lacks tools for considering the different levels of context that influence them. In other words, when analyzing inter-organizational dynamics, the theory of boundary objects is worth being combined with a broader theory which may help encompass the exterior constraints that impact projects. Regulation approach meets these preoccupations since it allowsus to consider territorial development projects as meso-systems, embedded in a regime of accumulation, and to understand the institutional arrangements as well as to question the meso-macro dialectic. This means our contribution emphasizes the fact that micro, meso and macro levels matter when IOC processes are brought back into scope.

The research design of the paper is based on a comparison between two territorial development projects. One of them is a territorial cluster of economic cooperation (PTCE), which aims at structuring and developing eco-construction sector in the French departments of Hautes-Alpes and Alpes de Haute Provence. The other is an emerging Mexican national park in Jalisco. Both of them are recent, considered as bottom-up initiatives, but show serious limits in keeping actors involved. The outline of the paper is, 1/ to present an original framework mixing the theory of boundary objects with the regulation approach for territorial development projects analysis ; 2/to describe detail the two case studies' processes by combining a boundary object perspective of making common sense and a multi-scalar observation of collaboration and its limits.

A BOUNDARY OBJECT APPROACH OF MAKING COMMON SENSE

The concept of boundary object was originally proposed to explain collaboration and conciliation of different viewpoints in scientific work. Star and Grisemer (1989) Boundary objects are described as : « objects which are both plastic enough to adapt to local needs and the constraints of the several parties employing them, yet robust enough to maintain a common identity across sites. » (Star & Grisemer, 1989). In other words, they both inhabit several intersecting social worlds and satisfy the informational requirements of each of them. Three components to boundary objects are particularly outlined : interpretive flexibility, the material structure of different types of boundary objects, the question of scale . The authors distinguish four forms of boundary objects : a repository, which takes the form of a set of modular things, ideal types, coincident boundaries and standardized forms. Many scholars have worked on the figure of boundary spanner, the one that relates practices of different fields. To a certain extent, this figure could be assimilated to the Callon and Latour's translator (1981), but has the particular interest to highlight the distinction between nomination and enactment (Levina, Vast, 2005). While some boundary spanners and boundary objects are simply nominated or designed to perform certain roles, others are « in practice» or « in use», in the sense that they are engaged or deployed in spanning boundaries separating fields.

The concept of boundary object has been important to recent contributions that have highlighted the role of translation between divergent viewpoints [START_REF] Granjou | Quand l'identité de l'objet-frontière se construit chemin faisant. Le cas de l'estimation de l'effectif de la population de loups en France[END_REF], especially in CSCW literature (Lutters & Ackerman, 2006) but so far have neglected the consideration of other levels of context. In particular, the current conceptualization of boundary objects seems insufficient to describe how IOC comes to happen or on the contrary why it doesn't as part of territorial development projects.Existing theories of collaboration fall short of explaining the embeddedness of scales that generates complex processes in this kind of projects.Those studying IOC through a single theoretical lens have tended to stay focused on issues that are defined as significant within their community of scholars [START_REF] Cropper | The Oxford Handbook of Interorganizational relations[END_REF] However, in order to analyze better the complexity of processes, the boundaries of theories being used to investigate IOC have began to intrude each other. It is precisely what we propose to undertake for understanding IOC in territorial development projects. Thus, in the next part,we build upon regulation approach to highlightthe articulation of the different scales that influence the projects.

A REGULATION APPROACH OF INTER-ORGANIZATIONAL COLLABORATION

The regulation theory was initially developed in the early 70s to explain economic instability and stagflation in France. Boyer (1990) defines it as follows : «The study of the transformation of social relations, which creates new forms-both economic and noneconomic-organized in structures and reproducing a determinate structure, the mode of reproduction». This model offers two principal concepts. While regime of accumulation is used to analyze the way production organizes and expands capital (Fordism for instance), mode of regulation refers to channeling of behaviors and reproduction of institutional forms.

The main institutional forms are : the institutional money form, the competition form, the wage form, the state form, and the international regime [START_REF] Boyer | La théorie de la régulation : une analyse critique[END_REF].

In this contribution, we prefer talking about territorial regulation and don't build upon regulation theory as conceptualized originally but rather on the recent contributions that focused on meso-macro dialectic. According to Dutertre and Laurent ( 2008) :«Territorial regulation results from the necessity to regulate conditions through which sectors are developed and resources are assigned». More specifically, in order to analyze IOC in territorial development projects, regulation approach allows to examine how institutional compromises are established.These projects deal with sustainable development and so can be interpreted as resistances to the regime of accumulation. The actors involved show willingness to « change the rules», and to set new norms on their territory, whether their intention is to develop new economic practices or to protect the environment.

METHODOLOGY, DATA COLLECTION

In this research, we seek to overcome monocausal explanations and monolevel analysis in the comprehension of IOC. Thus, the case study method lends itself very well to the comparative analysis of two territorial development projects. Indeed, our research question deals with complexity and process analysis of interactions and dependences, which are the main subjects of this method [START_REF] Wacheux | Méthodes Qualitatives de Recherche en Gestion[END_REF].We are convinced that an approach in terms of levels of analysis is both structuring and heuristic, and remains all too rare in management sciences (Lecocq, 2012). We used an abductive approach in thus study, relying on transcripts from semistructured, in-depth interviews with the actors of our two field sites : representatives andmembers involved in the projects, inhabitants of the territories covered by the projects and whose activities are concerned, and public actors who participate to the elaboration of local or national public policy. We conducted a total of 42 interviews : 28 for the first case and 14 for the second one. The first case study is based on our doctoral thesis realized in France 1 while the second one is issued from a research project in Mexico : Mi Sierra 2 , in which we participated for a four-month study of tourism sector. Additional data sources included internally generatedpresentations, reports3 , maps, and meeting notes. Regarding our research question, these case choices appear particularly interesting. We made the effort to choose particular cases precisely because they are special in the sense of allowing us to gain certain insights that other cases would not be able to provide [START_REF] Siggelkow | Persuasion with case studies[END_REF].

First, they illustrate very well initiatives supposed to be bottom-up but elaborated as public policy program. They also have the particularity to gather extremely diverse group of actors, which leads to an always negociated IOC. Then, they deal with two innovating projects, which purpose is both territorial development and establishment of new norms. Lastly, 1 « La coopération territoriale comme processus structurant de l'émergence d'éco-filières : le cas de deux PTCE de la région PACA », Céline Bourbousson, LEST 2 « Miradas e Investigaciones sobre la Sierra Occidental », research project lead by CEMCA and MNHN (Serge Bahuchet, Anouck Bessy and Delphine Mercier) and based on Anouck Bessy's doctoral thesis : « La gouvernance locale et les usages de la biodiversité par les populations dans le corridor Ameca-Manantlan, Jalisco, Mexique » theseinitiatives are embedded in two different macro contexts (France and Mexico), which allows us to question meso-macro dialectic overcoming national specificities.

COMPARATIVE ANALYSIS OF MAKING COMMON SENSE

In our two cases, we can identify a great diversity of boundary objects, used to create a common language between the different categories of stakeholders and social worlds. In this part, we describe the two more relevant ones and begin to analyze their similitude and their role.For PTCE eco matériaux, eco construction method takes on great importance and can be interpreted as a boundary object, enough to adapt to needs of each group of actors. The architects consider eco construction method as an opportunity to use new materials and see it as a way to improve the energy efficiency index. Among them, we can notice a difference of appropriation of the notion. Some of them consider the local origin of the materials used as a priority whereas others get them from other regions. For the militants, eco construction method means respect of the planet and is also a way to satisfy self production needs. For instance, one of the most involved actor of this group is interested in eco construction because he considers it as an alternative to conventional industry of construction. He organized activism for years to denounce pollution and danger for health that this industry implies and eco-construction is a way for him to combat this industry, proposing a« green » alternative.

For Work Integration Social Enterprises (WISEs), the meaning of eco construction method is very different as they see it as a source of employment. The biggest and most institutionalized WISE push the case for a large definition of eco construction, that wouldn't focus on the local origin of the materials but rather the potential of economic activity it would generate. Public institutions also share this perception but are more interested in the opportunity to reduce the local electricity consuming, that is very high in PACA despite of the clement weather. Thus, eco construction method can be interpreted as a coincident boundaries object (the third form of boundary object described by Star and Grisemer in their founding paper) since it has the same boundaries for each group -use of eco materials to improve energy efficiency -, but different internal contents -each group has its own criteria regarding which material or precise method is part of eco construction.

Regarding our second case, Paisaje Biocultural, the most significant and used boundary object is the label. With the creation of this new model of natural Park, a label will be elaborated, on the model of french parcs naturels régionaux. Local producers see it as a way to certify their production and benefit from a better promotion. For the town halls of the three villages concerned by the project, the label is an opportunity to encourage local production and consume and so to create economic activity.Then, actors of touristic sector consider the label as a way to promote the region. For them, it aims at constructing an identity in the territory. This group of actors is the privileged interlocutor of the project. Thereby, they have more influence than the others on the material structure of the boundary object and tend to project their own conventions on it.

FIRST SCALE OF ANALYSIS : ILLEGITIMATE BOUNDARY OBJECTS AND ISOLATION OF BOUNDARY SPANNERS

Two elements contribute to explain local difficulties, in the two cases, to enable IOC. First, boundary objects used to enhance collaboration have been designated within the framework of institutional initiatives, but still have not been appropriated by local actors. In the PTCE eco-construction, it results in the difficulties of the actors to agree on eco construction definition and to get involved for concrete actions, while in Paisaje Biocultural, it implies a differentiated involvement between touristic actors and the others. Then, boundary spanners also lack legitimacy.In PTCE éco-matériaux, the boundary spanners are the "employment area commitee" employees. Their job entails developing the production, transformation, distribution and use of local eco materials. Towards this end, they have to join together the actors of each material and scale, to make them inventing new ways of working together.

They manage a three-years-national grant which is supposed to unite stakeholders and strengthen the sector. However, they lament the fact that the actors don't get involved. The director comments : « I come from north of France and there I used to assist the elaboration of Agendas 21, it wasn't easy but people understood and got involved. Here it's "every man for himself" culture. » The boundary spanners have trouble establishing a consensus and a common comprehension at the boundary between local producers and public institutions.

Their speech, due to their former professional experience, is better fitted and familiar to public stakeholders than to farmers or artisans. One of them mentions explicitly : « we are not in the same world». This lack of legitimacy for the boundary spanners is also an obstacle for Paisaje Biocultural in Mexico. Indeed, most of the employees used to work together in CONAFOR (national forestal commission), which promoted Paisaje Biocultural but hadn't succeeded in gaining the trust of local actors.

Those explanations are interesting and relevant to examine why the nominated boundary spanners, in our two cases, have a hard time establishing a common language between the different groups of stakehoders. However, it would be simplistic to explain the local difficulties of IOC in the two cases without considering the contexts. We overcome the mono causal explanations in the following part by drawing on the regulation approach.

SECOND SCALE OF ANALYSIS : MESO AND MACRO TENSIONS

The two cases we study are local initiatives to create new territorial regulations. The french PTCE aims to develop new practices in terms of construction and employment while Paisaje Biocultural invents new ways of protecting natural resources and developing economic activity. In order to set these institutional arrangements, the actors involved in the projects have created boundary objects. Yet, their efficiency depends on a certain consistency between the different levels of context. Precisely, regulation approach permits to consider the embeddedness of the projects in various levels of context. The main institutional forms [START_REF] Boyer | La théorie de la régulation : une analyse critique[END_REF]) that interact and influence IOCare :the competition form, the international regime and the state form.

First, meso-analysis allowsto enlighten some obstacles that affect IOC. In France, the construction sector is dominated by big companies, which have used conventional and polluting materials. They are also very present in the certifying committee for materials (CSTB) and defend their interests. The PTCE eco-construction joins together activities using materials that are not certified, and so propose new conventions that are in contradiction with the institutional mechanisms of the sector. Moreover, national educative system doesn't value eco construction : knowledge and methods in this field lack capitalization. In Paisaje Biocultural, the touristic dimension is very important. However, tourism is one of the most influent industry in the country and it is precisely mass tourism that is promoted and sustained, while Paisaje Biocultural proposes ecotourism.

International competition also has an obvious influence on IOC. For instance in France, importations of wood from Eastern Europe have substituted for local wood because of very cheaper prices due to a modern production tool. In Mexico, tourism has been impacted by the recent increasing of international cheap destinations and its companies struggle to keep their market share. In the territory of Paisaje Biocultural, some big touristic companies have had an aggressive strategy, monopolizing most of the activity by organizing tours in the villages of the project.

CONCLUSION

In both cases, our results show the contractions between a territorial dynamic and its environment's one. [START_REF] Gilly | La dimension locale de la régulation[END_REF]. Indeed, this paper illustrates a typical situation.

The situation when the innovations thought in the territories, with the help of boundary objects -used to facilitate IOC-need, to develop and be effective, the split of institutional forms of national economic system. Yet, these innovations are local and don't have the potential to spread and transform the existing regime of accumulation and mode of regulation.

To understand why so-called bottom-up projects hardly ever succeeded in enabling IOC, it is useful to analyze creation or use of boundary objects, but also to consider the embeddedness of these local regulation initiatives in different scales of context. Thereby, it allows a whole understanding of processes involved in the establishment of institutional local compromises. This invites us to explore a question at the heart of regulationist problems : the important issue of determining the local conditions of recomposition of the accumulation regime. This questioning is part of the debate (local/global) opened and structured by three collections of essays (Storper, Scot, 1992, Benko, Dunford, 1991[START_REF] Benko | Les régions qui gagnent. Districts et réseaux : les nouveaux paradigmes de la géographie économique[END_REF].

  first analyzed the history of the Museum of Vertebrate Zoology at the University of California, with the ambition to examinehow the tension created by heterogeneity among the actors involved was managed. The model they propose differs from the Callon-Latour-Law one, by replacing the Obligatory Passage Point with other kind of translations. They retain two methods in order to ensure collaboration across divergent social worlds : standardized methods and boundary objects. We only focus on boundary objects, because of the characteristics of territorial development projects : they don't have sufficient routine work to map their processes.

  The two cases are 1/ a French territorial cluster of economic cooperation (PCTE) and 2/ an emerging natural Park in Mexico (Paisaje Biocultural).1/ In France, a PTCE is characterized by the union of social economy organizations, « classic » SME, local authorities and investigation centers for a local and sustainable project. The model was created in 2013 with an interministerial call for projects which selected 23 clusters in the country. PTCE eco construction is one of them and aims at structuring wood, straw, stone and clay filieres in departments of Hautes-Alpes and Alpes de Haute Provence. This cluster is managed by an «employment area committee», which is a french instance of broadened social dialog, and comes from an institutional diagnostic of region PACA. After the end of the public funding period, it is supposed to be autonomous, and managed by the local actors, members of the cluster's organizations. 2/ Paisaje Biocultural in Sierra Occidental de Jalisco region of Mexico, also deals with a new institutional figure. It was created as part of french-mexican international cooperation and aims at experimenting a new way of protecting the environment while developing local economy.

For instance, Bessy A., Sulmont A., Mercier D., Bahuchet S., 2014, 2ndo informe del proyecto de investigación MI SIERRA. Gobernanza y usos de la biodiversidad en la Sierra Occidental de Jalisco, https://halshs.archivesouvertes.fr/halshs-01216479