Lise Arena
email: lise.arena@univ-cotedazur.fr

Anthony Hussenot
email: anthony.hussenot@univ-cotedazur.fr

From Innovations at Work to Innovative Ways of Conceptualizing Organization: A Brief History of Organization Studies

Hussenot

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Introduction

While organizational scholars have recently investigated varied organizational phenomena, such as social movements, artistic activities, nonpro t organizations or informal collectives of people, mainstream organization research has historically carried out empirical work in companies, factories or networks of rms, 1 mainly because of the dominance 1 is proximity with business has led to a confusion between organization studies, management research (George 1968;Wren 1972) and the theory of the rm. Management research is interested in improving the economic performance of companies and organizations; the theory of the rm concentrates on the economic dimensions of rms. In this chapter, we suggest to highlight the distinction between organization studies, management research and the theory of the rm.

of the industrial context after the Second World War. As such, organization studies are rooted in social sciences (such as economics, sociology and philosophy), and focus on the evolution of work and management practices. As most of social sciences, organization studies have evolved in line with society, and more speci cally, business, managerial and work innovations. Consequently, the relation between innovations at work and the theoretical developments has led to di erent understandings of the matter of organization over time. If an organization was initially conceptualized as a social and/or economic entity evolving into an environment, this view has since been challenged by scholars. Recent organization theories have suggested to understand organization as an open phenomenon, always in a state of becoming. An organization is not conceptualized as an entity but as an elusive movement ongoing re/de ned in practices.

e initial essentialist view of organization was forged in a context of industrialization and mass production, dominated by Fordist practices, while the current elusive view of organization has emerged in the context of 'liquid modernity' [START_REF] Au | Liquid modernity[END_REF] and the 'projecti cation' of work [START_REF] Jensen | e projecti cation of everything: Projects as a human condition[END_REF].

In this chapter, we suggest studying the relation between work innovations and the evolution of organization theories. We emphasize the relation between management and work innovations and new ways of conceptualizing the matter of organization over time. e aim is to show how innovations at work have in uenced the way scholars have conceptualized organizational phenomena over time.

We describe and analyze this relation from the 1950s to the 2010s. We study this relation through four periods covering the mass productionbased organization of the 1950s to the projecti cation of work of the 2010s. Of course, these periods are used for analytical purposes as each new period partly overlaps with the previous ones.

Period 1: The Development of Industrial Innovations-Theorizing Organization as a Centralized Managerial Hierarchy

e period following the Second World War was marked by an unprecedented economic expansion in Western countries that depended on the signi cant rise of consumption and national modes of capitalism [START_REF] Arena | Les modèles nationaux d'enseignement de la gestion d'entreprise: Formes de capitalisme et modes d'organisation[END_REF]. Rising working-class prosperity led to mass consumption and Fordist mass production replaced manual work with machines leading to increased labor division and repetitive tasks. Social and technological changes that shaped the second half of the twentieth century built on the rst industrial revolution in the nineteenth century; the second industrial revolution was based on the development of organic chemistry, electricity and nuclear physics in the rst half of the twentieth century and molecular biology since the 1950s. Post-Second World War advances in engineering, computer science and electronics also paved the way towards the third 'electronic' industrial revolution characterized by a smaller number of rms than the ones that shaped the second industrial revolution. ese successive waves of inventions shaped industries all over the world, with Europe catching-up the US. e US developed innovations and gained competitive advantage in the computer (e.g. IBM) and car (e.g. General Motors) industries. In the same period, Europe gradually caught up particularly in the chemical (e.g. Haber-Bosch) and car (e.g. Volkswagen) industries in Germany and the transport industry in France (e.g. SNCF).

e UK di ered slightly as industrial policy was limited and most innovations appeared in the service industry (e.g. nancial sector). Organizational forms shaped by industrial innovations in this period resulted from national characteristics: managerial capitalism in the US, state-led nationalized enterprises in France, cooperative capitalism with cartelization in Germany and proprietary capitalism with family-owned businesses in the UK.

Centralized Managerial Hierarchies and the Rise of Professional Management

To a large extent, the main characteristics of organizational forms in the post-Second World War period appeared as a continuity of inter-war managerial innovations. Business historian Alfred Chandler claimed that the structures of companies and the role of management played a signicant part in the evolution of capitalism [START_REF] Chandler | Strategy and structure: Chapters in the history of the industrial enterprise[END_REF]). Hence, US capitalism success could be explained by the ability of American managers to develop multidivisional enterprises, characterized by centralized hierarchies, administrative coordination and the rise of managerial services. By contrast, British managerial backwardness was due to the predominance of small rms (mostly family-owned businesses) and a small number of 'white collars'. 2 Innovations were supported by "the new forms of transportation and communication [which] permitted the rise of modern mass production. […] us, came into being a new economic institution, the managerial business enterprise and a new subspecies of economic man, the salaried manager" (Chandler 1990, 1). ese organizations appeared as an alternative to decentralized market mechanisms and they routinized transactions among units, lowering their costs. Organizational models were based on administrative coordination and task specialization that allowed product speci cations and market services to be adjusted more rapidly to customer needs. At the management level, salaried middle and top managers supervised and controlled the di erent units. As a result, management became a profession with a direct interest in organization (and innovation), in contrast to shareholders who were still generally driven by short-term pro t interest.

Based on this vertical integration model inherited from Frederick Taylor's "Principles of Scienti c Management" ( rst published in 1911) and labor division popularized by Henri Ford, managers and workers of the 1950s took part in a large transformation of work practices. On the one hand, control was placed at the center of managerial corporations, as managers of multidivisional units were the guardians of standardized methods. e professionalization of management and the emergence of salaried managers justi ed the development of management education in the US and in Europe which soon became an urgent need to train this new category of businessmen [START_REF] Arena | Les modèles nationaux d'enseignement de la gestion d'entreprise: Formes de capitalisme et modes d'organisation[END_REF]). Yet, over the 1960s, the topdown understanding of control gradually faded away to allow more room to a consensual view of the employment contract in which workers could develop further adaptability and gain welfare.

On the other hand, the inheritance of Taylor's methods stimulated labor movements which later encouraged the consideration of employees' working conditions and the creation of research committees in America and in Britain to address the 'labor problem'. During the inter-war period, 'labor problems' were due to high turnover, high absenteeism and low workers' motivation and drove employers in large businesses to think about the relationship between workers' welfare and productivity. It was in this context that a number of American rms-such as Proctor & Gamble, General Electric, Eastman Kodak and U.S. Steel-began to develop a range of new initiatives about work welfare that took the form of nancial and non-nancial measures. 3

Pioneer Organization Theories: The Tavistock Institute, the Aston Group and the Carnegie School Pre-1945 ideas about management and organization developed by engineers such as Henri Fayol, Henri Ford and Frederick Taylor equipped enterprises with new forms of labor specialization that were disseminated beyond America, as the most e cient mode of organization in industrial factories. Although Europe never witnessed a 'scienti c management' movement like its American equivalent, Taylorism and Fordism still received a fair amount of attention, mainly positive, by British, French 3 is included measures to improve basic working conditions (e.g. provision of shower rooms, cafeterias and drinking fountains), to enhance workers' sense of being part of a factory team (e.g. publication of company magazines, organization of educational lectures and athletic clubs), to recognize seniority in employment status (e.g. bonuses, pension plans, medical assistance and company housing) and to provide training opportunities (e.g. vocational schools and apprenticeship programs) (Moriguchi 2000, 13-14).

and German engineers [START_REF] Chevalier | La technique de l'organisation des entreprises-Livre 1: Le gouvernement de l'entreprise[END_REF][START_REF] Whilston | e reception of scienti c management by British engineers: 1890-1914[END_REF]. Moreover, the theoretical analysis of bureaucracy by sociologist Max [START_REF] Weber | Economy and society[END_REF], translated and expanded upon by Talcott [START_REF] Parsons | Max Weber and the contemporary political crisis[END_REF][START_REF] Parsons | Introduction[END_REF] and Robert Merton (1949Merton ( /1968)), played an important role in the development of early organization theories [START_REF] Shenhav | e historical and epistemological foundations of organization theory: Fusing sociological theory with engineering discourse[END_REF]. is is exempli ed by the publication of the rst academic articles about organization such as the work of sociologist Philipp Selznick who published An Approach to a eory of Bureaucracy in 1943 and Foundations of the eory of Organization in 1948. In the same period, Herbert Simon published in 1947 American Behavior: A Study of Decision-Making Processes in Administrative Organization. As a result, new modes of organization in industrial factories and pioneer publications in the eld led to the emergence of three major schools of thought: e Tavistock Institute (London, UK), the Aston Group (Birmingham, UK) and the Carnegie School (Pittsburgh, US).

e Tavistock Institute: e Working Group as a Sociotechnical System e rst wave of reactions to the scienti c method of organizing enterprises comes from the 'human relations' movement. is movement was exempli ed by the Hawthorne studies-some of the best known and most in uential investigations in the history of organizational researchthat took place at the Western Electric Company (US) between 1927 and 1932. In the same period, the French industrial engineer Henri Fayol (1916Fayol ( /1949) put a greater (than Taylor) emphasis on the management level (and less on the workers) and discussed the aim of the managerial function. 4 Management anticipates actions (planning), aims at structuring the organization (organizing), disseminates orders (commanding), guarantees the coherence of actions (coordinating) and checks results (verifying).

Social psychology of work and early studies on groups as organizations went one step further and signi cantly rose in the UK in the 1960s. In particular, Eric Trist, with a number of colleagues in the Tavistock Institute (such as Emery, Rice and Miller), conducted a series of investigations into groups and organizational functioning. eir main contribution to the emergence of organization studies led to a 'system approach' to organizational behavior. In particular, they showed that working groups were neither a social system nor a technical system but an interdependent sociotechnical system. In their view, the traditional technocratic bureaucracy is limited when organizations have to face turbulent and innovative environments. Control systems could be seen as cumbersome and costly even if, thanks to this control, an unskilled worker in a narrow job is inexpensive to replace and takes little time to train. As early as the 1960s, these authors suggested alternative organizational designs for turbulent environments in which "individuals and units have wide repertories of activities to cope with change", and an improved quality of working life "by keeping the technological determinants of worker behavior to a minimum to satisfy social and psychological needs by the involvement of all" (Hickson andPugh 2007/1964, 153).

e Aston Group: e Structure of Organizations e structuralist view was deeply anchored in Max Weber's contribution to sociology and its translation in English by Talcott Parsons. A small interdisciplinary (social psychology, sociology, anthropology, political science and economics) group of researchers (1961)(1962)(1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970) at the University of Birmingham in the UK echoed this initial trend and sought to understand variables in uencing organizational structures (such as technology, size, environment and culture). 5 Aiming to make a contribution to the interdisciplinary study of management behavior, the Aston group tested the idea that organization structure ts its operational context (Greenwood and Devine 1997, 202). Based on a statistical analysis, the group, whose principal investigators were Derek Pugh and David Hickson, collected rms' data that enabled them to build organizational taxonomies. In this sense, the Aston Group's contribution to organization theory also has to be assessed at a methodological level since it was seen as "somewhere in between the tracing of processes over time in early "one case-studies […] and the postulating of causal explanations informed by wider sampling" (Pugh and Hickson 1972, 273). eir willingness to develop from a descriptive to an analytical discipline led the Aston research team to initiate 'strategic contingencies theories' in a research cooperation with the University of Alberta in Canada.

e Carnegie School: Decision-Making Processes in Organizations

In the last chapter of his book e Functions of the Executive published in 1938, Chester I. Barnard, President of the New Jersey Bell Telephone Company at the time, observed that there was a need for "a science of organization" (Barnard 1968(Barnard /1938, 290), 290). 6 e publication of Herbert Simon's Administrative Behavior in 1947 explicitly relied on Barnard's e ort to develop a science of organization. Simon's initial ambition was to formalize Barnard's contribution from a conceptual perspective. He sought to "describe, in words, exactly how an administrative organization looks and exactly how it works" [START_REF] Simon | Administrative behavior: A study of decision-making processes in administrative organization[END_REF]). Simon's concept of 'bounded rationality' directly contributes to the development of organizational theory, as organizations are seen as useful instruments "for the achievement of human purpose". 7 Organizations are therefore seen as a way to economize on cognitive resources, seen as scarce in a context of bounded rationality. Simon discussed innovation in relation with a 6 Barnard identi ed this gap in social sciences: "there is no science of organization or of cooperative systems; and the development of the sciences called social has clearly lagged far behind those called physical and mathematical. One reason for this appears to be a false emphasis upon intellectual and mental processes both as factors in human relations and as matters of study" (Barnard 1968(Barnard /1938, 290), 290). 7 Herbert A. Simon challenged the well-established concept of 'perfect rationality' used at the time in economics. For him, human cognitive capabilities are limited in information and knowledge and cannot formulate a 'rational' choice resulting from an optimization process. Humans simplify their choice process and can do so when replacing the goal of 'maximizing' with the goal of 'satis cing'.

problem-solving framework. Innovation (technical or organizational) is seen as a signi cant process in the expansion of rms. As innovation and creativity are a type of complex problem-solving, he argued that it could be captured in terms of simple heuristics and satis cing criteria (by contrast with optimization which was the predominant paradigm in economics at the time). Simon's contribution to 'design science' paved the way towards new models of innovations mainly based on knowledge transfers and information-based approaches.

To a large extent, the publication of Simon and March's book on Organizations in 1958, and Cyert and March's book in 1963, imported innovation issues in organization theories. In particular, Cyert and March argued that their general theory was "of considerable relevance to the prediction of innovations" (1963,278). ey focused on the notion of failure and argued that rms innovate both when successful and unsuccessful. In the case of successful rms, the existence of organizational slack allows resources to be channeled towards innovative activities. In the same vein, they showed that, in service organizations, managers "prefer to copy the ideas of others or to search for ready-made solutions instead of seeking innovation" (Nutt 1984, 445). ey linked innovations with the concept of 'organizational learning', as rms revise their search procedures on the basis of experience (Cyert and March 1963, 124).

is rst period constituted the rise of management as a profession with "concepts, research methods, and specialized techniques of practice that could be studied, taught, communicated and improved by the acquisition of scienti c information" (Scott 1992, 25). Organizations were seen as administrative entities and closed systems in which innovation was attributed to the visionary capacities of top managers. As rightly stated by Slappendel (1996, 110), in this perspective, "the actions of individuals are not seen to be constrained by external factors, instead individuals are perceived to be self-directing agents who are guided by the goals that they set".

Period 2: Immaterial Innovations and the Knowledge-Based Economy-Theorizing Organization as a Learning Institution

e second period of analysis is concerned with the development of the 'electronic' century [START_REF] Cortada | Information and the modern corporation[END_REF], also characterized as the second wave of the Information Technologies (IT) revolution enabled by the advent of the personal computer during the 1980s and the Internet during the 1990s [START_REF] Porter | How smart and connected objects are transforming competition[END_REF]. Innovations are essentially immaterial and developed within the context of a global knowledge economy, with distributed supply chains easing coordination and integration across activities. From the 1980s onwards, large managerial corporations turned into innovative enterprises characterized by coordinated business organizations that adopted technologies and learned to adapt in a context of high uncertainty and turbulence. In the US, the Management in the 1990s Research Program, a close collaboration between academic researchers at the MIT Sloan School of Management and representatives of major corporations, represents the organizational archetype of the 1990s and their organizational, work and technological innovations. e nal report of the program strongly emphasized the role of information in the evolution of 1990s rms (Scott Morton 1991). Information was considered, for the rst time, as a fourth factor of production: "as an 'information engine', it can do for business what the steam engine did in the days of the Industrial Revolution" (Scott Morton 1991, 8). e di usion of IT implied potential organizational change, as it o ered the opportunity for organizations to react constructively to environmental turbulence. In the 1980s, most technological innovations were concerned with hardware, software, networks, workstations robotics and smart chips. ese information-based technological innovations gave rms the opportunity to lower their operating costs while improving their e ciencies [START_REF] Cortada | Information and the modern corporation[END_REF][START_REF] Porter | How smart and connected objects are transforming competition[END_REF]. For example, in the 1990s, the emergence of supplychain enhanced the coordination of work and the management of ows of goods, supplies, processes and expenses within the organization.

L. Arena and A. Hussenot The Knowledge-Based Economy and Horizontal Informational Structures of Companies

While the US economy had a signi cant competitive advantage with a well-established IT industry composed of large corporations such as IBM and Microsoft, the Japanese computer industry arose in the 1980s, from capabilities developed in long-established rms making electrical and telecommunications equipment, such as Fujitsu Limited or Toshiba Corporation. is has to be understood in relation with the evolution of Japanese capitalism based on nancial business and conglomerates. e Japanese industrial success of the 1980s was mainly explained by national speci cities such as stable shareholding, permanent employment and main-bank lending [START_REF] Lazonick | Innovative business models and varieties of capitalism: Financialization of the U.S. Corporation[END_REF]. In his comparison of two archetypal rms (the American and the Japanese models), the economist Masahiko Aoki observed the rise of the Japanese economy in the 1980s and explained it through a shift from primary and secondary activities (agriculture and manufacturing) to information-based production (telecommunications and computers 8 ). e Japanese organizational model paved the way towards a knowledge-based economy 9 characterized by exible specialization, mass customization and lean manufacturing. e shift from a vertically integrated organization to a more exible way of organization is largely rooted in the archetype of 1980s Japanese rms.

e development of horizontally coordinated organizations led to various changes in the nature of work. is period constituted a breaking point with the Fordist era. " e heightened expectations of people in Western Europe and North America are giving rise to pressures to improve 8 is phenomenon was also observed in the US to a lesser extent at the time under the term "Post-Fordism". 9 While embryonic approaches of information and knowledge-based organizational theories originated in the 1960s, they only became popular 30 years later. One example of this theoretical trend is probably the dissemination of resource-based approaches to the rm as a result of Edith Penrose's early contribution to organizational theory. In her 1959 book, entitled e eory of the Growth of the Firm, Penrose views rms not like standard economists of her time as price (and output) takers whose access to extra-pro ts is limited to situations of high degrees of market power (imperfect competition). Instead, she emphasizes that the rm is a device for innovation, problem-solving and cumulative learning through production. She underlines the idea of an endless knowledge-creating process and argues that "the very processes of operation and of expansion are intimately associated with the process by which knowledge is increased" (Penrose 1959, 125). the quality of working life and the quality of the environment. is is resulting in a changing concept of what constitutes value" (Scott Morton 1991, 3). In addition, cooperative work enabled by IT tended to alter most tasks in organizations, as the primary objective of organizations moved to coordinate the delivery of goods and services to customers. As a result, traditional roles of managers changed, as employees had "more access to data, they will take over many of the functions associated with supervisors" (Osterman 1991, 236). Managers had to learn to share their knowledge of the production process and of technologies with less qualied workers. As teams became a more common organizational form within rms, workers also had to learn new roles and skills. Jobs were no longer speci ed in detail and workers had to rotate among various jobs, and the development of skills and tacit knowledge became key to rms' strategies.

New challenges faced by organizations involved a need to train high skilled workers and to develop a 'learning organization'. erefore, knowledge gradually became one of the most important assets in the development of rms' competitive advantage. e practice of knowledge management was introduced as "the identi cation, optimization, and active management of explicit or tangible informational assets (such as data physically stored in a computer or on a piece of paper) and tacit knowledge (information and insights residing largely in people's heads)" (Cortada 2011, 24). In line with this knowledge-view of the organization, communities of practice emerged as triggers to collective 'learningby-doing' and started attracting scholars' attention [START_REF] Lave | Situated learning: Legitimate peripheral participation[END_REF]. New forms of learning organizations rely on the growth of communities of practice with people who share a concern or a passion for something they do and learn how to do it better as they interact regularly. during the 1980s and 1990s to either reinforce the mainstream perspective in organization studies or disrupt it by introducing alternative ways of de ning and studying organization. To exemplify this tension in the eld, the following section introduces the neo-institutionalism, the postmodernism and the critical management studies.

Reinforcing the Mainstream or

Neo-institutionalism: Isomorphism and Legitimacy

From the 1950s, the notion of 'organizational behavior' has been dominant in organization studies. e premise of organizational behavior studies is that an organization is an entity that can (almost) behave on its own. However, others have argued that society and institutions in uence this behavior. During the late 1970s, a new form of institutionalism, called 'neo-institutionalism', emerged to understand how organizational behavior is situated and in uenced by other organizations and wider social forces [START_REF] Lounsbury | Neo-institutional theory (Management Oxford bibliographies[END_REF]. For these scholars, any organization evolves in communities of organizations that interact with each other [START_REF] Dimaggio | e iron cage revisited: Institutional isomorphism and collective rationality in organizational elds[END_REF]. ese interactions create an 'institutional logic', that is symbolic and material elements tied together and providing order and meaning [START_REF] Friedland | Bringing society back in: Symbols, practices, and institutional contradictions[END_REF]. According to the neo-institutionalist view, organizations conform to institutional prescriptions to gain legitimacy with key audiences [START_REF] Meyer | Institutionalized organizations: Formal structure as myth and ceremony[END_REF]. Legitimacy is understood as immaterial capital enhancing status, reputation and survival chances [START_REF] Rao | e social construction of reputation: Certi cation contests, legitimation, and the survival of organizations in the American automobile industry; 1895-1912[END_REF]. Organizations implement innovations as a way to conform with institutional logics, and not necessarily because of requirements of technical, human or nancial e ciency.

ese institutional pressures lead to 'isomorphism' among organizations, that is organizations imitate each other by adopting common structures, practices and technologies [START_REF] Meyer | Institutionalized organizations: Formal structure as myth and ceremony[END_REF]. Unlike organization theories developed in the rst period, the focus of neo-institutional theory is not the relation between the organization and its environment, but rather networks of organizations, such as innovation systems.

AU8 AU9

Postmodernism: e Role of Language in the Emergence of Organizational Phenomena

As much as neo-institutionalism can be understood as expanding mainstream organization studies, the postmodern perspective was developed by some scholars in organization studies during the 1980s and the 1990s and initiated a radical change in the way organization has been studied since. However, the notion of postmodernism covers at least two di erent meanings: postmodernism (without a hyphen) as a way of studying organizational phenomena [START_REF] Cooper | Modernism, postmodernism and organizational analysis: An introduction[END_REF][START_REF] Burrell | Modernism, post modernism, and organizational analysis: e contribution of Jürgen Habermas[END_REF][START_REF] Cooper | Modernism, post modernism and organizational analysis: e contribution of Jacques Derrida[END_REF][START_REF] Chia | From modern to postmodern organizational analysis[END_REF][START_REF] Chia | Organization theory as postmodern science[END_REF][START_REF] Parker | Post-modern organizations or postmodern organization theory[END_REF]; and the postmodern organization (with a hyphen) as a type of organization emerging during the 1980s and the 1990s [START_REF] Clegg | Modern organizations: Organization studies in the postmodern world[END_REF].

Postmodernism is rooted in European philosophy of the 1970s and 1980s, in particular the French theories of Jacques Derrida, Michel Foucault and Jean-François Lyotard, among others.

e postmodern view insists on the role of language in constituting organizational phenomena. In such a view, there is no ultimate truth about organization and management but only forms of discourses. Postmodernism is thus based on a critique of positive and normative science seeking laws for good practices, which is the foundation of modernist organization studies and management. Instead, postmodern scholars urge scholars to study the situatedness of organizational phenomena and how they are performed through discourses.

e postmodern perspective characterizes a new form of organization as exible and niche-marketed and based on a multi-skilled workforce held together by IT networks and outsourcing (Clegg 1990, 181). ese new organizational forms are claimed to be innovation-oriented, organizational structures exible with no clear center of power or spatial location. Japanese innovative working methods illustrate the postmodern organization. Japanese engineers designing products followed the product from the lab to the manufacturing facility [START_REF] Aoki | Toward an economic model of the Japanese rm[END_REF]). Workers had to become capable of coping with unexpected emergencies as managers increasingly delegated their decision-making power. Knowledge had to be shared and the new challenge was the codi cation and transmission of L. Arena and A. Hussenot tacit knowledge from expert to non-expert workers, and the organization had to develop learning and adaptation capabilities, rather than concentrate on minimizing transaction costs. is organizational form follows a just-in-time production process which begins when customers order a product and in which each worker has skills to adapt to this new type of production.

Critical Management Studies: e Deconstruction of Hidden Assumptions in Management

Partly based on the postmodern turn, some scholars have started to question the assumptions of management both as an academic discipline and as a practice. is has led to the emergence of critical management studies (CMS), rst initiated by [START_REF] Alvesson | Critical management studies[END_REF]. According to critical management thinkers, modern management is mainly instrumental and only serves the pro t of companies [START_REF] Adler | Critical management studies[END_REF]). Innovations at work such as improvement of working conditions, selfdevelopment and self-determination are only adopted by companies if they help to improve business performance. is raises ethical and political questions regarding the value of such ends, and consequently, the responsibility of scholars reinforcing such practices through normative research and teaching. "CMS aims to show how such beliefs and practices are nurtured by, and serve to sustain, divisive and destructive patterns and structures; and also, how their reproduction is contingent and changeable, neither necessary nor unavoidable" (Adler et al. 2008, 3). CMS aim at denunciating the instrumentalism, patriarchism, racism, imperialism, productivism (etc.) that are inherent in modern management.

Period 3: Liquid Modernity-Theorizing Organization as a Movement

In 2000, sociologist Zygmunt Bauman published a book called Liquid Modernity. is book marked a turning point in social sciences as his key idea is that we have been entering a society in which the core institutions are diluting. e expression 'liquid modernity' was a way to express one of the main trends of our society: the liquefaction of social institutions. For Bauman (2000), this liquid modernity means that individuals can rely only on themselves as their relations with others are uncertain, evolving and temporary. Jobs, family, friendships are becoming more and more uncertain, often in a state of ux. ere are many explanations for this liquefaction of society and some of them can be found in the countercultures of the 1960s and 1970s, when people started to free themselves from rigid social orders (religion, patriarchism, patriotism, etc.). However, in the 2000s, the world became more globalized than ever, with largescale exchanges between people. With the end of the Soviet Union at the beginning of the 1990s and market deregulation all over the world, cultures and economies became more globalized and a reality that people could experience in their daily life. is globalization generated a period of economic growth and social development for many countries, but at the same time, an intensi cation of competition between companies. Outsourcing, o shoring, mergers and acquisitions were the main consequences of this erce global competition.

Innovation as the Main Driver in Management

To face these threats, companies had to innovate constantly, again and again. is has become a motto in many sectors. Of course, innovation had been a key activity for companies for decades, but the novelty became the intensity of innovation. Instead of waiting for the end of their products' life cycle before launching a new one, companies started to constantly launch new products on the market as a way to beat competitors.

is period of development coincided with the second wave of IT-driven transformation, characterized by the rise of the Internet with its cheap and ubiquitous connectivity [START_REF] Porter | How smart and connected objects are transforming competition[END_REF]. is led to enhanced coordination between suppliers and customers across space and time. is innovation intensity is not only the result of increased competition, it is also the sociological consequence of the liquefaction of society. As people's identity was no longer based on belonging to institutions AU10 L. Arena and A. Hussenot (company, family, state, etc.), mass consumption became a way to de ne oneself [START_REF] Au | Liquid modernity[END_REF]. Consumption is motivated by the desire to become someone and belong to groups sharing the same consumption. As innovation became the only way to make business, management and work practices became more knowledge-oriented in order to generate more ideas. is is referred to as the knowledge-based economy, an economy in which knowledge is considered as the core asset and provides competitive advantage for companies. e 2000s was the age of knowledge management, competencies management, communities of practices, learning organizations. All of these notions and managerial practices have aimed at ensuring constant learning, sharing, storing and creation of knowledge for the sake of innovation. Technologies also played an important role in this evolution, as the fast development of the Internet during the 1990s and 2000s and the constant improvement of computers and infrastructures have enabled people to work together and access large amounts of information. ese technological developments also participated in the innovation race. Information systems management became another crucial area for companies, as information systems were considered a key element to compete in this knowledge-based economy.

Towards 'Organizational Mindsets': The Process View, Practice-Based View and Sociomateriality

Facing this globalized world in which companies were constantly evolving, merging with each other, diversifying their activities, competing and partnering on a global level, organizational scholars could not rely on the essentialist view of organization any longer-the organization as an economic or social entity. Inspired by postmodernism in organization studies [START_REF] Parker | Post-modern organizations or postmodern organization theory[END_REF][START_REF] Chia | From modern to postmodern organizational analysis[END_REF][START_REF] Chia | Organization theory as postmodern science[END_REF], but also by feminists Judith Butler and Karen Barad and posthumanists Andrew Pickering and Bruno Latour, organizational scholars shifted from a quest to develop ultimate explanations about the organization to developing organizational 'mindsets' [START_REF] Cabantous | Seeing the potentialities at the intersection: A re ection on performativity and processuality mindsets[END_REF], that is a way to provide plausible accounts about how organizational phenomena are produced and maintained on a daily basis by actors. An organization is no longer a company AU11 but a constant process of de ning outputs and inputs of activities. [START_REF] Chia | Essai-irty years on: From organizational structures to the organization of thought[END_REF][START_REF] Chia | A 'rhizomic' model of organizational change and transformation: Perspective from a metaphysics of change[END_REF] expanded on this idea arguing that organization is a process of world-making. An organizational phenomenon is an ontological activity that consists in de ning the world, a situated de nition of the world in order to act. By distinguishing the notions of organization as an ontological activity from company as a legal object, the study of organizational phenomena belonging to this globalized world became possible.

ese mindsets are based on two core premises. e rst is the primacy given to action, what people do. Organizational phenomena emerge and are maintained only through action. is moves away from the essentialist view that gave primacy to the organization. e second premise is based on relational ontology [START_REF] Slife | Taking practice seriously: Toward a relational ontology[END_REF][START_REF] Cooper | Relationality[END_REF]. Relational ontology means that everything exists only in relationship to other things. ' ings' have not inherent properties and their singularity emerges from their interrelatedness. Interrelatedness is not passive and imposed on 'things'. According to the principle of action, it is in action that technologies, rules, roles, statuses and so on are mutually de ned. Many 'mindsets' have been developed based on these two premises: performativity [START_REF] Gond | What do we mean by performativity in organizational and management theory? e uses and abuses of performativity[END_REF], the narrative approach [START_REF] Rantakari | Narratives and processuality[END_REF], the communication constitutive organization [START_REF] Cooren | Communication, organizing and organization: An overview and introduction to the Special Issue[END_REF], the process view [START_REF] Langley | Introducing perspectives on process organization studies[END_REF], the practice-based view [START_REF] Gherardi | How to conduct a practice-based study: Problems and methods[END_REF], sociomateriality [START_REF] Orlikowski | Sociomateriality: Challenging the separation of technology, work, and organization[END_REF]) and so on. ey all put action rst, but have suggested di erent foci, such as language, social practice or technologies. As a way to exemplify this stream of research, we outline below three key 'organizational mindsets': the process view, the practice-based view and sociomateriality.

e Process View: Understanding Organization as a Movement e process view is anchored in postmodernism and process philosophy which draws on various philosophers from the pre-Socratic Greek philosophy of Heraclitus to the metaphysics of Alfred North Whitehead, the American pragmatism, German phenomenology, Henri Bergson, Gilles Deleuze and so on [START_REF] Rescher | Process metaphysics: An introduction to process philosophy[END_REF][START_REF] Rescher | Process philosophy: A survey of basic issues[END_REF]Helin et al. 2014). eir key assumption is that reality is constantly owing and we cannot really grasp L. Arena and A. Hussenot it, but only create images as a way to make it tangible and actionable (Bergson 2009(Bergson /1907)). [START_REF] Cooper | e open eld[END_REF][START_REF] Cooper | Relationality[END_REF][START_REF] Cooper | Organs of process: Rethinking human organization[END_REF][START_REF] Cooper | Process and reality[END_REF] and [START_REF] Chia | From modern to postmodern organizational analysis[END_REF][START_REF] Chia | Essai-irty years on: From organizational structures to the organization of thought[END_REF][START_REF] Chia | A 'rhizomic' model of organizational change and transformation: Perspective from a metaphysics of change[END_REF][START_REF] Chia | Organization theory as postmodern science[END_REF] de ned key principles of the process view. Action and relational ontology are two of them, but the originality has been to add the principle of immanence [START_REF] Chia | A 'rhizomic' model of organizational change and transformation: Perspective from a metaphysics of change[END_REF]. Immanence means that everything exists in the current moment. e past, the present and the anticipated future are not a series of separate events, but are co-de ned and co-rede ned in the current moment. In other words, past events can always be reinterpreted according to the evolution of action, while anticipated events can always be rede ned. It means that current action always brings the past, present and anticipated events. Key challenges of process organization scholars are to understand constant change [START_REF] Tsoukas | On organizational becoming: Rethinking organizational change[END_REF]) and how 'things' occur and are maintained in a constantly owing world.

e Practice-Based View: Understanding Organization from Practices e practice-based view is the second main mindset that has in uenced organization studies since the 2000s. Practice-based studies are rooted in the work of various sociologists and philosophers such as [START_REF] Bourdieu | Esquisse d'une théorie de la pratique[END_REF][START_REF] Bourdieu | Esquisse d'une théorie de la pratique[END_REF], [START_REF] Lyotard | La Condition postmoderne[END_REF][START_REF] Foucault | Power/knowledge: Selected interviews and other writings 1972-1977[END_REF], [START_REF] Taylor | Philosophical arguments[END_REF] and [START_REF] Giddens | Central problems in social theory[END_REF][START_REF] Giddens | e constitution of society[END_REF]. Pierre Bourdieu and Anthony Giddens can be considered as the key inspirations for organizational scholars. For Bourdieu [START_REF] Bourdieu | Esquisse d'une théorie de la pratique[END_REF], the world is made objective through practices, while [START_REF] Giddens | e constitution of society[END_REF] insists on the role of social practices in the making of social structures. e main assumption of the practice-based view is that organizational phenomena are not given but emerge and are maintained through practices [START_REF] Schatzki | Social practices: A Wittgensteinian approach to human activity and the social[END_REF][START_REF] Schatzki | Introduction. Practice theory[END_REF][START_REF] Corradi | rough the practice-lens: Where is the bandwagon of practice-based studies heading?[END_REF]. For these authors, the practice-based view is thus a "way of seeing", with the aim of understanding "the situatedness of practical reasoning and the contingent nature of organizational rationality" (Corradi et al. 2010, 268). However, the concept of practice is di cult to de ne as practice can be anything participating in the shaping of the social world. Generally speaking, practice is simply what actors do with rules, words or things. e

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practice-based view is about understanding how everyday activities produce, reproduce or transform social structures "that are at the heart of collective action" (De Vaujany et al. 2016a, 25). Consequently, the unit of analysis becomes what actors do, or make visible through their actions.

Sociomateriality: e Relation Between the Social and the Material

During the 2000s the matter of materiality regained popularity among organizational scholars, partly due to the ubiquity of technologies at work. A stream of research called sociomateriality (with or without a hyphen) emerged as a way to study the entanglement of the social and the material. Mainly anchored in agential realism [START_REF] Barad | Posthumanist performativity: Toward an understanding of how matter comes to matter[END_REF][START_REF] Barad | Meeting the universe halfway: Quantum physics and the entanglement of matter and meaning[END_REF], posthumanism [START_REF] Pickering | e mangle of practice: Time, agency, and science[END_REF], actor-network theory [START_REF] Latour | Reassembling the social. In An introduction to actor-networktheory[END_REF]) and the practice-based approach in organization studies [START_REF] Orlikowski | Using technology and constituting structures: A practice lens for studying technology in organizations[END_REF], studies focused on how the social and the material gain status and roles through their intertwining in practice [START_REF] Orlikowski | Sociomateriality: Challenging the separation of technology, work, and organization[END_REF][START_REF] Au ; Introna | Otherness and the letting-be of becoming: Or, ethics beyond bifurcation[END_REF][START_REF] Jones | Untangling materiality[END_REF][START_REF] Shotter | Re ections on sociomateriality and dialogicality in organization studies: From 'inter-' to 'intra-thinking'… in performing practices[END_REF]). Here again, primacy is given to action and the relational ontology. Entities "have a shared being and a mutual constitution" (Slife 2004, 811). From this entanglement perspective, any separation is merely analytical [START_REF] Orlikowski | Sociomateriality: Challenging the separation of technology, work, and organization[END_REF], as what we call the technical, the social and the organizational are mutually constitutive, only existing as doing [START_REF] Shotter | Re ections on sociomateriality and dialogicality in organization studies: From 'inter-' to 'intra-thinking'… in performing practices[END_REF] in their radical otherness (Introna 2013). e core question of this research stream has been how 'matter matters', and more importantly how entities matter in practices, how forms and their relations appear (Jones 2013, 223). ese mindsets can be considered as renewing ontological debates about organization. However, they have been confronted to their own contradictions about the ontology of organizational phenomena. Contradictions have come from the way scholars have dealt with relational ontology. In most of these mindsets, scholars' work can be divided into two groups: advocates of a weak relational ontology versus advocates of a strong relational ontology [START_REF] Slife | Taking practice seriously: Toward a relational ontology[END_REF]). In the weak relational ontology, 'things', such as actors, technologies, roles, statuses, have their own existence. Despite their interaction and imbrication, 'things' remain L. Arena and A. Hussenot distinct, interdependent phenomena. Strong relational ontology states that 'things' do not exist on their own but are entangled and intertwined; 'things' gain status only through their interpenetration and intra-action [START_REF] Barad | Posthumanist performativity: Toward an understanding of how matter comes to matter[END_REF]. A more managerialist view of these mindsets has also emerged. Anchored into weak relational ontology, it has attempted to provide managerial contributions as a way to help companies face economic challenges.

is can be found in various research streams in between management research and organization studies, such as strategyas-practice, community-of-practice, sociomateriality (with a hyphen) and the weak process view dedicated to the understanding of the innovation process.

Period 4: Working and Collaborating Without a Company-Current Developments in Organization Studies

In 2008, the nancial crisis revealed an ugly truth to the world. e banking system had played dangerously with people's money leading to a dramatic economic crisis, seizure of properties, bankruptcies, unemployment and so on. e consequences were dreadful and governments all over the world tried desperately to contain the crisis. is crisis made more visible social challenges such as wealth inequality and unemployment. is led to an unprecedented crisis of faith that has since nurtured various social movements and political extremism. At the same time, environmental challenges have become more urgent. Climate change, scarcity of resources, pollution, loss of biodiversity, deforestation have started to question the industrial and mass-consumption model. e risk of a global collapse is considered a serious scenario by numerous scientists. In such a context, a rather young, educated, globalized and progressist elite-often ironically called hipsters-has been experimenting with alternative lifestyles and new ways of working, living and consuming. Living and gentrifying neighborhoods of big cities, such as East London, they have developed a new economy called the ' at-white economy' by [START_REF] Mcwilliams | Flat white economy: How the digital economy is transforming London & other cities of the future[END_REF], based on alternative ways of manufacturing and consuming. Veganism, eco-friendly products, the sharing economy, personal development have become some of the key trends; while the development of new digital and mobile technologies such as social media, smartphones and high-speed mobile networks enable them to develop their business from anywhere.

Against the 9 to 5 Office Job: The Lifestyle Entrepreneurship ese people are the tangible manifestation of many changes in society, especially at work. ey tend to reject the traditional employment culture, that is 9 to 5 o ce hours, the hierarchy, job titles and the perks among others, and embrace 'lifestyle entrepreneurship, that is a strong belief in self-empowerment through entrepreneurship. Many terms have been proposed to name these new workers: mumpreneurs, makers, digital nomads, creative freelancers, in uencers, coworkers, solopreneurs and so on. Most of the time they are independent workers, working collaboratively with other independent workers or companies. ey reinvent ways of collaborating by relying on online platforms or social media or joining a shared working space such as a coworking space or a makerspace. Hypothetically they can work where and when they want, on the projects they want to, with whom they want and with no subordinate relation with anyone [START_REF] Hussenot | Collaborating without formal organization[END_REF]. is 'lifestyle entrepreneurship' also means that work and life are not separate activities any longer, and the entrepreneurial activity serves a lifestyle. e notion of 'workation' is a good example of this renewed relationship between work and life as it expresses the idea that work and vacation could be experienced at the same time. However, this idealistic scenario (as it has often been depicted on social media, blogs and press articles) has been tarnished by the so-called gig economy-short-term tasks-based activity carried out by independent workers-which has brought uncertainty and nancial insecurity to many workers [START_REF] Acquier | Promises and paradoxes of the sharing economy: An organizing framework[END_REF]. Car drivers and riders delivering food are two of the most common examples of this gig economy in which workers are paid per task.

L. Arena and A. Hussenot

Theorizing Organization Without a Company: Towards New Challenges and Frameworks in Organization Studies

In such a fast changing and interrelated world, theories and mindsets developed during the 2000s have served as a core background for organizational scholars. ere is still a need for strong philosophical and social theories as foundations to understand current trends. Critical management studies, the process view, practice-based theory and the performativebased view are still playing an important role in the intellectual debate. Awareness of this changing global context has encouraged organizational scholars to research new topics such as social movements [START_REF] Haug | Organizing spaces: Meeting arenas as a social movement infrastructure between organization, network, and institution[END_REF][START_REF] Yous | Rethinking hybridity in postcolonial contexts: What changes and what persists? e Tunisian case of Poulina's managers[END_REF]), bikers' collectives [START_REF] Wilhoit | Collective action without organization: e material constitution of bike commuters as collective[END_REF] or terrorist networks [START_REF] Schoeneborn | Clandestine organizations, al Qaeda, and the paradox of (in)visibility: A response to Stohl and Stohl[END_REF][START_REF] Stohl | Secret agencies: e communicative constitution of a clandestine organization[END_REF]. Traditional topics such as management and work are explored through the lens of these global trends; changing work practices are happening outside of big companies and often deal with social, economic and environmental challenges. For instance, freelancers, makers and coworkers question our assumptions about working space, working time, but also collaboration, leadership, collective identity, power relations and so on and traditional dualisms such as work versus life, social concerns versus economic ones, companies versus their environment and so on. ese dualisms seem to disappear in our interrelated world. Social, environmental and economic challenges have been at the heart of debates for the last decade and the study of companies has become less of a priority. is has been called the 'societal turn in organization theories' (De Vaujany et al. 2016b 'Organizing for a sustainable future: Responsibility, renewal and resistance' (2020).

eoretically speaking, the current challenge is to envisage organizational phenomena not only as open but also uid [START_REF] Schreyögg | Organizing for uidity? Dilemmas of new organizational forms[END_REF], where activities and relationships are constantly evolving, members are not clearly identi ed and boundaries are open or permeable [START_REF] Blagoev | We are all 'herd animals': Community and organizationality in coworking spaces[END_REF][START_REF] Dobusch | Fluidity, identity, and organizationality: e communicative constitution of anonymous[END_REF]. In such organizational phenomena, work can be done not only anywhere and at any time, but in multiple spatialities and temporalities. Another challenge is to conceptualize organizational phenomena with no separation between work and life. is is, for example, the case with in uencers who have built their business based on their private life (Du y 2016), or digital nomads who have decided to travel the world, while their professional activity is carried out exclusively remotely [START_REF] Arena | Digital nomads beyond the buzzword: De ning digital nomadic work and use of digital technologies[END_REF]. As a way to understand these open and uid organizational phenomena, new theoretical concepts have been suggested recently. For instance, the concept of 'organizationality' [START_REF] Dobusch | Fluidity, identity, and organizationality: e communicative constitution of anonymous[END_REF][START_REF] Schoeneborn | e communicative constitution of organization, organizing, and organizationality[END_REF][START_REF] Blagoev | We are all 'herd animals': Community and organizationality in coworking spaces[END_REF]) and the events-based approach (Hernes 2014a, b;[START_REF] Hussenot | Encompassing stability and novelty in organization studies: An events-based approach[END_REF][START_REF] Hussenot | L'organisation à l'épreuve des makers[END_REF][START_REF] Hussenot | Studying organization from the perspective of the ontology of temporality: Introducing the events-based approach[END_REF].

Organizationality: Understanding Organization as an Adverb

In 2015, Dobusch and Schoeneborn introduced the notion of organizationality to understand how organizational dynamics manifest themselves in uid organizational phenomena. ey suggest to understand organization as an adverb [START_REF] Schoeneborn | e communicative constitution of organization, organizing, and organizationality[END_REF]). e organization is what characterizes the organizing process (in the same way that the adverb is what characterizes the verb). e organization is what quali es the activities. An organization is not an entity but the very de nition of the activity (goal, purpose, roles, actors, coordination modes, etc.). e authors invite us to rethink dynamics such as collective identity, actorhood and the interconnected instances of decision-making in uid organizations [START_REF] Dobusch | Fluidity, identity, and organizationality: e communicative constitution of anonymous[END_REF]. is approach recognizes the existence of organizational dynamics in uid organizational phenomena, but emphasizes their emergent, openness and situated nature. ese authors L. Arena and A. Hussenot propose an interesting approach, as understanding organization as an adverb is a stimulating way to study how organizational dynamics are produced and reproduced by actors, whichever their activities and their interrelatedness with all aspects of actors' life. is approach o ers an alternative way to analyze organizational identity, actorhood and decisionmaking without necessarily ascribing mechanisms to actors.

Events-Based Approach: Understanding Organization as a Temporality

As an attempt to o er an alternative way of thinking and studying organization, Hernes (2014a, b) has suggested to focus on events and temporality. Based on this, [START_REF] Hussenot | Encompassing stability and novelty in organization studies: An events-based approach[END_REF], [START_REF] Hussenot | L'organisation à l'épreuve des makers[END_REF], [START_REF] Hussenot | Studying organization from the perspective of the ontology of temporality: Introducing the events-based approach[END_REF] have developed the events-based approach. It suggests that organizational phenomena are temporal, emerge and are maintained through the ongoing con guration and co-de nition of past, present and future events that de ne both the current moment and the continuity of the activity. e events-based approach suggests to shift from an essentialist view of organization-that is a view reducing organization to an entity delimited in space and time-to a view in which the organization is a shared history, past, present and future, that enables actors to act collectively. In such a view, 'things' such as rules, technologies, actors and so on gain a meaning, a role and a status through this enacted temporality. Any 'thing' is understood as a temporal phenomenon. Conversely, these 'things' also participate in the co-de nition and con guration of the past, present and future events [START_REF] Hussenot | L'organisation à l'épreuve des makers[END_REF]) and organization is de ned as a structure of events (Hernes 2014b). By reframing ontological categories (events and not things) and the ontological dimension (situated temporality and not time and space) of organizational phenomena, the events-based approach o ers an alternative to understand phenomena in which there is no given space, boundaries, members and so on; but a continuous movement of de ning activities in which various actors, technologies, goals, histories and so on are delineated through a shared temporality. e events-based approach is an attempt to study these lique ed, nomadic and rhizomic contemporary organizational phenomena.

Conclusion

Based on a historical perspective, the aim of this chapter was to enquire about the way innovations at work have in uenced organization theories over time. By focusing on the interrelations between technological innovations, the evolution of organizational phenomena and evolutions of ways of working, we have argued that organization theories have evolved along with innovations at work. is historical attempt opens new avenues of research in both organization studies and organizational history which could provide a better understanding of current work practices as being part of a more 'longue durée' phenomenon in line with the evolution of capitalism. For example, longitudinal studies and monographs on the evolution of work practices in companies could provide further material to think about current and future work practices as evolutions anchored into past transformations.

  ese managerial innovations and generally speaking the social and intellectual contexts of the 1960s and 1970s inspired organization scholars L. Arena and A.Hussenot

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  ). Recent themes addressed at the European Group for Organization Studies conferences (the main European research associa-

	tion in organization studies) speak for themselves: 'Bridging continents,
	cultures and worldviews' (2013), 'Reimagining, rethinking, reshaping:
	Organizational scholarship in unsettled times' (2014), 'Organization and
	the examined life: Reason, re exivity and responsibility' (2015), ' e
	good organization: Aspiration, interventions, struggle' (2017),
	'Enlightening the future: Challenge for organization' (2019) and

Further details about the history of organization and management studies at Birmingham can be found in[START_REF] Minkes | Early years in University development in management education: Re ections and reminiscences on the University of Birmingham (1950s-1970s)[END_REF]. AU5

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The citation "Bergson, 1907" has been changed to "Bergson, 2009"Bergson, /1907" to match the author name/date in the reference list. Please check if the change is ne in this occurrence and modify the subsequent occurrences, if necessary.

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The citation "1990" has been changed to [START_REF] Bourdieu | Esquisse d'une théorie de la pratique[END_REF] to match the author name/date in the reference list. Please check if the change is ne in this occurrence and modify the subsequent occurrences, if necessary.

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The citation "1990" has been changed to [START_REF] Bourdieu | Esquisse d'une théorie de la pratique[END_REF]


MONTHS

by WHO (2011) Of infants are breastfed AT BIRTH in France

Infant Formula

➔ Trp, a limit for reducing protein content in IF (Lönnerdal & Lien, 2003) Only a few study on tryptophan content and its bioavailability in human milk (Darragh, Moughan, 1998 ;Maathuis et al., 2017)

-Scientific context

SEROTONIN

Neuronal development contribution (Heine, 1996) Link between serotonin and behaviour regulation (Fernstrom, 2012;Young et al.,1985) Effect of serotonin on sleep, food intake and digestion (Le Floc'h et al., 2011) 03

MELATONIN

sleep/-wake balance (Aparicio et al., 2013) Behaviour (Le Floc'h et al., 2011) Memory and learning (Macchi and Bruce, 2003) Immune activity (Szczepanik, 2007) Antioxydant properties (Heine, 1995) Pineal gland

INDOLE

 inflammation (Shimada et al., 2013) Epithelial barreer integrity (Bansal et al., 2010 ;Shimada et al., 2013) ⚠ High concentration:  anxious and depressed behaviour (Hayatt MIR, 2018 ;Jaglin et al., 2018) Bacterial metabolism

  BIOAVAILABILITY: nutrient fraction digested, absorbed by intestinal mucosa and available for subsequent body metabolic functions → True ileal digestibility is a good proxy(Fuller & Tomé, 2005) DIGESTIBILITY CALCULATION:Total N flow (g/g DMI) = N ileum × Marker meal Marker ileumApparent ileal digestibility: Apparent ileal digestibility (%) =Dietary N intake -Total N flow ileum Dietary N intake ×100Standardised digestibility(Rutherfurd et al., 2006):Standardized ileal digestibility (%) = Dietary N intake -N exogenous flow ileum Dietary N intake ×100Standardized ileal digestibility (%) = Dietary N intake -(Total N flow ileum -N endogenous flow ileum )

-Results: Ileal Digestibility -Tryptophan

	Principal use of Trp : anabolism
	Secondary use of Trp : catabolism
	-	Major pathway
	-	Minor pathway


Camille Benaroch
email: camille.benaroch@inria.fr

Camille Jeunet

Fabien Lotte

Lotte Fabien

Mi-

MI-BCI Performances correlate with subject-specific frequency band characteristics

Introduction: Motor Imagery (MI) tasks modulate EEG activity, notably in the α and β frequency bands (8-30 Hz). During BCI calibration, data driven methods are often used to select features in those bands, with little consideration for the resulting human performances. Can this approach reach optimal performances? To answer this question, this study investigated the relationship between the characteristics of subject-specific frequency bands selected by machine learning (mean frequency (FB-Mean) and length (FB-Length)) and online BCI users' performances.

Material, Methods and Results: We analysed the data of 59 healthy MI-BCI naïve subjects from the dataset presented in [START_REF] Roc | Would Motor-Imagery based BCI user training benefit from more women experimenters?[END_REF]. Each subject was trained to perform two MI-tasks -imagining rightand left-hand movements -during one MI-BCI session (6 runs of 20 trials/MI-task: 2 calibration runs and 4 feedback runs). From the calibration runs, we selected the most discriminant frequency band in the α-β range using the algorithm introduced in [START_REF] Blankertz | Optimizing spatial filters for robust EEG single-trial analysis[END_REF]. MI-BCI performance was assessed as the classification accuracy (CA) averaged over all feedback epochs during the feedback runs. We then studied how the FB-mean and FB-length obtained using machine learning were related to online CA, by studying their correlation and distribution. The results showed a significant Pearson correlation between mean CA and both FB-Length (r = 0.67, p<0.001) and FB-Mean (r = -0.34, p<0.01) (see also Fig. 1).

Discussion: The characteristics of the frequency band selected by machine learning correlated with online CA. Subjects with the highest CA were the ones for whom the selected frequency bands were narrow (FB-Length: ~[2-6] Hz) and centered in α-lowβ (FB_Mean: ~[11-20] Hz).

Significance: Our study suggests that online MI-BCI performances correlate with the characteristics of the frequency band, selected using machine learning. This raises questions regarding the causality link direction: could we use this frequency band to predict online performances? Could we improve machine learning algorithms with constraints on the band to be selected? Is this correlation due to a covert confounding factor (e.g., mental strategy)?

Figure 1 .

 1 Figure 1. Bivariate distribution of the frequency band length (a) and the mean frequency of the band (b) with the mean classification accuracy. In red, the chance level for 2-classes, 80 trials per class and α=5%

Acknowledgements: This work was supported by the European Research Council with project BrainConquest (grant ERC-2016-STG-714567).


Isaac Martens

Antonis Vamvakeros

Nicolas Martinez

Raphaël Chattot

Janne Pusa

Maria Valeria Blanco

Elizabeth A Fisher

Tristan Asset

Sylvie Escribano

Fabrice Micoud

Tim Starr

Alan Coelho

Veijo Honkimäki

Dan Bizzotto

David P Wilkinson

Simon D M Jacques

Frédéric Maillard

Laetitia Dubau

Sandrine Lyonnard
email: sandrine.lyonnard@cea.fr

Arnaud Morin
email: arnaud.morin@cea.fr

Jakub Drnec
email: drnec@esrf.fr

Imaging Heterogeneous Electrocatalyst Stability and Decoupling Degradation Mechanisms in Operating Hydrogen Fuel Cells

come

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Large scale adoption of hydrogen energy systems requires reliable, cost competitive water electrolyzers and fuel cells, of which the polymer electrolyte membrane (PEM) variants are most popular. 1 The performance and cost are both driven by design of a multi-layered nanocomposite membrane electrode assembly (MEA). [START_REF]Annual Merit Review and Peer Evaluation Report[END_REF] Despite great progress in optimizing individual components of the PEM fuel cell (PEMFC) MEAs in laboratory model systems [START_REF] Chen | [END_REF]4 , these advances have not always translated into improved performance at the device level 5 7 , because strong interactions between different components and the complex chemical environment of an operating cell hinders the integration of each component into an optimized MEA architecture 6,8 . These effects apply not only to catalyst activity, where poisoning of the Pt surface by ionomer is increasingly recognized as a limiting factor, 7 but also to water/thermal transport, electrolyte stability, and myriad other issues related to integrated systems engineering. 9 Improving the durability of high performance catalysts presents a great challenge and is limited by our understanding of the degradation phenomena. 10,11 Carefully balancing the performance, durability, and cost of the oxygen reduction reaction (ORR) catalyst is necessary for technological advancement of PEMFC systems. 12 The degradation processes of Pt-based ORR catalysts have been rigorously investigated under idealized laboratory conditions (i.e. in inert atmosphere, room temperature, and ultrahigh purity liquid electrolyte). The oxidation and reduction of the Pt surface plays a central role 13 with potential cycles triggering nanoparticle reconstruction and dissolution 14 . This leads to corrosion, Ostwald ripening and coalescence of the nanoparticles during operation, lowering the surface area and mass activity of the catalyst. 15 The extent to which catalyst activity and durability measurements under idealized conditions transfer directly to the hot, gas phase polymer electrolyte MEA environment, remains an open question 16 , and the answer will guide development of active materials and operating protocols towards more robust performance. While much is known about degradation occurring specifically inside MEAs 6,8,9,12,15,17 22 , direct cell performance prediction based on rotating disc electrode studies remains challenging, especially for nanostructured catalysts, due to the phenomena discussed above.

Techniques which can simultaneously probe all the components of functional devices at the nanoscale are urgently required to optimize the MEA architecture and operating conditions. Spectromicroscopy approaches using electron 23 , neutron 24 , and photon beams 14,21,25 are powerful, but generally laborious and/or limited to ex situ experiments. Significant advances in spatial and time resolution with in situ X-ray absorption tomography have been recently achieved. 26,27 However, spatial resolution is often limited to scales greater than 100 nm and lacks the critical nanoscale and chemical information about the catalyst and supporting materials. This information is necessary to connect the catalyst activity, morphology and stability to the overall MEA performance. 28 These properties determine the device's life cycle, with major impact on its economic feasibility. 22 Here, we study the catalyst degradation phenomena in an operating PEMFC using novel high energy X-ray scattering techniques, simultaneously mapping chemical composition with X-ray diffraction computed tomography (XRD-CT) and nanostructure by small angle X-ray scattering computed tomography (SAXS-CT) across the device scale of several centimeters (Fig. 1A). 29 31 XRD-CT has been previously used to investigate solid oxide fuel cells 32 , catalytic reactors 33 and batteries 34 from hundreds of micrometers up to millimeters in size and provides atomic scale information about the used materials. To understand the degradation phenomena at the device level, we have extended these techniques to samples 10x larger than previously possible, such that entire X-ray transparent 5 cm 2 PEMFCs 35 can be imaged (Fig. 1A). The voxel size (200 µm x 200 µm x 50 µm) shown here is currently limited by the beam size and measurement speed, and can be optimized for larger devices down to sub-micrometer resolution using 4th generation X-ray sources. Detailed descriptions of the method are available as supplementary information.

Major advancements in computed tomography algorithms allow a direct observation of the rapid heterogeneous nanostructural deterioration of the MEA. Catalyst aging was explored under two different degradation conditions: under a potentiostatic hold at 1 V, and through a commonly used cyclic voltammetry accelerated stress test (AST). The catalyst degradation is directly linked to the formation of chemical and/or temperature gradients, correlated to the water distribution in the cell materials, and imprinted by the macroscale geometry of the flow field. Evidence of heterogeneous aging has been previously observed in end-of-life samples using ex situ analysis with TEM 18 or X-ray diffraction 20 . Characterizing and predicting the gradients at different operating conditions and integrating the structural evolution of electrocatalysts with fuel cell design will be increasingly necessary to mitigate degradation and lower the cost of the technology.

3D chemical mapping using X-ray scattering tomography Figure 1. In situ X-ray scattering tomography of a fuel cell membrane electrode assembly. A) Schematic of the grazing incidence diffraction tomography. B) Chemical maps of tomography slices collected through the cathode, PFSA membrane, and anode and obtained by simple deconvolution of reconstructed XRD patterns. Each map in B) is 1.9 cm across, 200 µm resolution, measured over the central region covered by the flow field of the 5 cm 2 cell. The cell was operated at 80°C and 100% relative humidity. The three slices were collected at 1 V, and during operation at 0.6 V, 1 A/cm 2 . C) SAXS tomography of slice through the PFSA membrane in a separate experiment, collected at 0.8 A/cm 2 , 75°C, 80% relative humidity. The color indicates the d-spacing of the ionomer phase segregation, reflecting local hydration.

The main advantage of XRD-CT is its superior chemical contrast in comparison to standard absorption-contrast tomography (Fig. 1B). The chemical maps, which can be merged into 3D images (Fig. S1), reflect the intrinsic heterogeneous nature of the PEMFC largely imprinted by the flow field design. The color mapping is normalized for each phase to the highest intensity detected across all three slices. Compression of the flow field induces wrinkling in the MEA, on the order of a few microns, generating lined patterns in the Pt and ionomer signals (note that the parallel channels of the cathode and anode plates were aligned perpendicular to each other). 19 This heterogeneous pressure field alters mass and thermal transport, as well as the mechanical properties of the electrodes, generating chemical gradients (H2O, O2, pH, Pt 2/4+ ) inside the cell and defining the nanoscopic degradation phenomena in the catalyst layer, which we will show later.

One of the most important aspects of fuel cell operation affected by the flow field is the water transport and distribution inside the catalyst layer, gas diffusion layer, and ionomer membrane, which is critical for obtaining maximum cell performance. 26,36 XRD-CT allows the spatial distribution of liquid water to be obtained from the amorphous background of the XRD patterns (Fig. 1B, detail in S5). The water distribution obtained in this manner is shown for slices collected at two different conditions: i) at 1 V, ~0 A/cm 2 and, ii) at 0.6 V, where the cell is operating at high current density (1 A/cm 2 , 0.6 W/cm 2 ). Differences in the quantity and distribution of water are detected throughout the device (Fig. 1B, far right column) and local water accumulation is observed, especially inside the ionomer membrane under the landing areas where the flow field structure touches the MEA. While not rigidly ordered, X-ray scattering from the ionomer produces several features over a very wide angular range, including the well-known nanoscale ionic/hydrophobic phase segregation (~0.15 Å -1 , Fig. S16), and semicrystalline packing of the backbone matrix (~2.5 Å -1 , Fig. S5). Unfortunately, the water, ionomer and carbon content in pixels containing large quantities of Pt (i.e. inside the catalyst layer specifically) is difficult to obtain as the weak scattering from the light materials is masked by the high attenuation of Pt.

These limitations can be addressed by imaging hydration gradients inside the cell with SAXS-CT, which is extremely sensitive to ionomer hydration. The phenomena of water collecting underneath the fuel cell flow fields has been studied for decades using X-rays 37 and neutrons 17,38 . Quantitative measurements of ionomer nanostructure by SAXS add significant value to standard water imaging experiments, since hydration inside the polymer electrolyte can be precisely determined. 39,40 SAXS-CT allows the spatial correlation of ionomer nanostructure, with the water content in the other cell constituents while using the same X-ray probe. A SAXS-CT slice collected in a separate experiment during cell operation (0.8 A/cm 2 , ~0.59 V, 80% relative humidity) reveals the heterogeneous hydration of the membrane throughout the MEA with significantly better detail than in the XRD measurement (Fig. 1C). The SAXS curves were modelled as a power law background with a Gaussian ionomer peak (Fig. S16). 41 The thin membrane was not perfectly aligned with the plane of the slice, so we restrict our analysis to the regions where the ionomer peak is clearly visible. Comparatively wet and dry regions inside the membrane can be resolved through changes in the d-spacing of the ionomer peak which indicates the distance between ionic nanodomains increases from 3.5 to 3.8 nm in the preferentially hydrated regions . The wet and dry regions exhibit a vertically lined pattern correlated with the positions of the flow field. This pattern is similar to the water distribution from the XRD-CT measurements, validating the data obtained by less precise XRD pattern analysis (note that the cathode and anode flow field ribs were aligned parallel to one another for the SAXS imaging). The SAXS shows that the membrane is partially hydrated, about 10% by weight (fully hydrated membranes contain up to 25% water 42,43 ). Streaks in the SAXS-CT image show the membrane underneath the flow field rib is preferentially hydrated pointing to the same hydration distribution pattern within the membrane as the liquid water in the carbon diffusion layers observed previously. 38 SAXS-CT analysis confirms that the nanoscale spatial heterogeneities arising from significant hydration gradients are correlated to the flow field pattern. Heterogeneity in the XRD-CT images is therefore also likely connected to the inhomogeneous distribution of water inside different layers of the device.

Degradation after a potentiostatic hold at 1 V

To correlate the water distribution inside the cell to the nanostructural heterogeneity of the catalyst and aging mechanisms within the MEA 44,45 the XRD-CT patterns. The intensity parameter of the Pt diffraction signals corresponds to the quantity of material, while the peak widths are related to the average particle size and defect content of the Pt catalyst. The main complication limiting such analysis on full scale operational devices are peak broadening artefacts known as parallax errors (i.e. peak broadening as a function -CT images of large samples >1 cm have until now limited the quality and reliability of nanostructural parameters obtained from the diffraction data (e.g. lattice parameter, peak widths). 35 Here we disclose a new tomographic algorithm called Direct Least-Squares Reconstruction (DLSR) which provides a generalized solution to this problem, and corrects for parallax distortion in arbitrarily large samples. Therefore, the practical maximum sample size for XRD-CT is limited only by penetration of the X-ray beam. This advance extends the capabilities of scattering-contrast tomography from laboratory specimens to samples normally imaged using hospital-style CT scanners, including practical fuel cell devices. The DLSR algorithm quantitatively recovers the diffraction profile (Figs. S11-S15) and the microstructure of the Pt catalyst in the fuel cell, including the particle size and strain. The computationally expensive nature of the parallax-corrected reconstruction currently limits the image resolution, although rapid advances in software capability are expected. A detailed discussion on parallax artefacts, its correction using the DLSR algorithm, and benchmarking versus conventional algorithms can be found in the Supplementary Information.

Figure 2 shows images of the Pt nanostructure obtained from Rietveld analysis of a single XRD-CT image slice collected through the cathode of a degraded MEA during operation at 1 A/cm 2 .

The degradation was induced by holding the potential at 1 V for 10 hours at 80°C, which is slightly above open circuit voltage (ca. 0.95 V). 15 These high, cell reversing potentials lead to Pt oxidation and degradation. 46 Variations in the Pt intensity map (Fig. 2A), reflect the mechanical distortion of the catalyst coated membrane inside the pressurized cell during operation. The region where the ionomer membrane protrudes into the measured slice shows particles up to 100 nm in size (yellow arrow, in Fig. 2B). While degradation gradients through the cross-section of catalyst layers have been previously reported using ex situ TEM 18,47 , the size of the Pt nanoparticles in the region of these protrusions are an order of magnitude larger than expected. Nanoparticles of this size are typically found in the "Pt band", formed near and inside the membrane of aged MEAs. 48,49 Even though the formation of this Pt band has been identified as a key factor in the stability of fieldtested MEAs 50 , in situ detection of Pt band formation has not been previously reported. Higher resolution imaging and aging conditions which emphasize Pt band formation will be necessary to confirm the localization of these large Pt particles inside the membrane. The central region of the sample (Fig. 2B, magenta arrow) can be seen in greater detail in Figs.

2C & D. Although the spatial resolution of these parallax corrected images is limited (500 µm) the particle size in the sample at the beginning of testing (Fig. 2C) is much more spatially homogeneous than after testing (Fig. 2D). Higher spatial resolution XRD-CT images can be obtained if parallax correction is neglected (Figs. 2E and2F, 200 µm resolution), with the tradeoff that the calculated particle sizes are qualitative and only comparative analysis is possible.

Vertical and horizontal streaks are visible in the uncorrected maps, where the particles are systematically larger in regions covered by the flow field plates. Therefore, the morphological degradation of catalyst nanoparticles in these regions is more severe, coincident with previously observed thinning of the membrane and local Pt corrosion. 51,52 The specific factors responsible for this nanoscale heterogeneity at high potentials are not easily decoupled. However, the link between flow field design and water content detected by SAXS-CT, and the correlation to the water distribution in the cell with catalyst degradation suggests that locally altered concentration and mass transport of dissolved species (O2, H + , Pt 2/4+ ) underneath the flow field ribs enhances degradation. A detailed understanding of how these complex gradients produce heterogeneous aging requires further study under well-defined aging conditions, likely guided by input from the growing fuel cell modelling community.

Degradation during accelerated stress testing in PEMFC vs conventional cells

Given the heterogeneity observed inside the catalyst layer during aging in an operating PEMFC device, the relevance of aging data from laboratory model systems deserves scrutiny because catalyst durability is principally assessed using cyclic voltammetry in ultrahigh purity liquid electrolyte at room temperature on a rotating disc electrode (RDE). 53,54 To evaluate the differences in these environments, the most popular catalyst AST protocol (sweeping between 0.6-1.0 V at 50 mV/s with Ar atmosphere on the cathode) was employed on the same commercial catalyst (Fig. S21) inside the PEMFC and with a conventional three electrode RDE cell. 2 X-ray diffraction was measured in situ at multiple locations in the cathode throughout the AST of the PEMFC sample and transmission electron microscopy (TEM) images were collected for both the PEMFC and the RDE cell catalyst at the beginning and end of the test.

Both catalyst particle ripening and dissolution of Pt in the PEMFC sample are directly observed during the AST. The mean crystallite size of the Pt increases from 4.6 nm to 10.3 nm (Fig. 3,top) and approximately 30% of the Pt in the cathode dissolved (Fig. 3, bottom), which is consistent with previous work. 14,46 Neither parameter follows a linear trend with the number of cycles: a large fraction of the overall change takes place in the first few cycles and the degradation slowly diminishes in effect without reaching a plateau. 44 As anticipated, the catalyst in the PEMFC aged dramatically faster than inside a conventional RDE cell. These differences can be attributed to the PEMFC environment, including higher temperature, lower pH, and enhanced mass transport of dissolved species, all of which promote corrosion of metallic catalysts. Although no tomography was performed, XRF mapping of the MEA sample after ageing showed that the dissolution was fairly homogeneous and XRD at multiple locations, both in the channels and landing areas, yielded similar results (Fig. S26). These data indicate that the chemical environment created inside the fuel cell during this AST profile is more homogeneous than the cell degraded by potentiostatic hold at 1 V, and questions the utility of current ASTs to assess catalyst stability during PEMFC operation. This is because the chemical and temperature gradients, which define the degradation dynamics as discussed above, are linked to faradaic reactions, and are suppressed during stress testing under inert atmosphere. Therefore, the only reliable way to benchmark the catalyst stability, is to study the materials in a PEMFC device during operation. Furthermore, the predictions obtained from laboratory model systems are substantially and systematically different than catalyst degradation in devices.

Distinguishing catalyst degradation mechanisms through XRD

Studies which track the dissolution of Pt inside operating PEMFCs are relatively rare. In this case, the quantity of Pt observed in situ by XRD can be correlated to the electrochemical surface area (ECSA) of the catalyst measured throughout the test. The ratio of the ECSA to Pt loading throughout the AST is related to the surface-area-to-volume ratio of the catalyst, which can be used to probe degradation mechanisms, since different mechanisms produce characteristic trends.

Processes such as local electrochemical disconnection, surface activation, or partial corrosion or larger particles produce increasing ECSA / loading ratios. Aggregation and ripening degradation modes produce decreasing ratios, while catalyst detachment from the support followed by dissolution would maintain a constant ratio. The observed trend is the sum of all simultaneous degradation modes. The shape of the normalized ECSA / Pt loading curve for the MEA is presented in Figure 4A. The ECSA is initially unstable and reaches a maximum after the first 100 cycles (attributed to surface cleaning), even though 12% of the Pt loading dissolves during this activation phase. The ECSA / Pt loading ratio then decreases smoothly between cycle 100 and 10000. During this second phase, only 16% of the catalyst dissolves/detaches, but 63% of the ECSA is lost to ripening, aggregation, and other mechanisms altering the morphology, but not the quantity of Pt.

The large difference between these numbers highlights both the importance of Pt redeposition and particle-particle interactions in the degradation mechanism of commercial PEMFC catalysts, and how Pt corrosion represents just one (but critical) step. We predict that the aging of shapecontrolled catalysts under well-defined conditions would benefit even further from direct measurements of surface area to volume ratios during operando experiments. The ratio of the ECSA to crystallite size by XRD allows ripening and aggregation degradation mechanisms to be decoupled. The observed crystallite size is unaffected by aggregation, but responds to ripening/coalescence processes, while the ECSA is sensitive towards both. The loading calculated on an absolute scale. The electrochemically connected fraction, dispersion, or m the ratio of the ECSA and this XRD calculated surface area (XRD-SA). Aggregation would cause the observed ECSA / XRD-SA ratio to decrease, while coalescence and ripening produce either higher or constant values depending on the catalyst morphology. The total surface area of the catalyst measured by cyclic voltammetry and calculated by XRD in cm 2 , along with the ECSA / XRD-SA ratio of the two are shown in Figure 4B. The catalyst was approximated as monodisperse spheres, with no corrections for surface area blocked by carbon support, electrochemically disconnected particles or aggregation.

Following the initial 100 cycles over which the catalyst surface is cleaned and the ECSA increases, the ECSA/XRD-SA ratio decreases to 64% at 1000 cycles, then increases and stabilizes at 70-71% for the remainder of the AST. We attribute these changes to an aggregation phase, followed by coalescence and ripening. The total range of the ECSA/XRD-SA ratio is relatively stable (64-78%), even though the total surface area changes drastically over the course of the AST. This indicates that aggregation processes only account for a few percent of the changes in ECSA, while coalescence and ripening phenomena are responsible for the majority of the decrease in surface area. The ~70% accessibility of the total Pt surface calculated from XRD is physically reasonable considering both the simplicity of this model, and that the carbon support and Pt aggregates block

Figure 2 .

 2 Figure 2. XRD-CT of Pt cathode catalyst. A) Pt intensity distribution over the single CT slice.

Figure 3 .

 3 Figure 3. Particle size (top) and percentage of Pt remaining in electrode (bottom) over 10 4 cycles

Figure 4 .

 4 Figure 4. A) Ratio of metallic Pt to ECSA remaining as a function of AST cycle number. Both

  the remaining ~30% of a Pt surface. The drastic loss of cathode ECSA during the AST produces clear performance degradation of the PEMFC device, as shown in the ORR polarization curves collected before and after the AST (Fig. 4C). The deep structural insight provided by operando XRD greatly enhances the value of even simple AST experiments on standard commercial catalysts. Ratios of microstructural parameters allow the contributions of competing degradation mechanisms to be decoupled. Major advances in XRD-CT reconstruction algorithms allow for simultaneous assessment and chemical heterogeneities inside an operational 5 cm 2 . Interactions between different phases can be correlated at high current densities with a single probe. The XRD-CT images provide nanoscale information and show spatially resolved differences in the aging of catalyst particles, which correlate to the flow field geometry and water distribution within the device observed by SAXS-CT. Therefore, the macroscopic design of the cell has a decisive role in the nanoscopic degradation phenomena of the catalyst, which needs to be taken into account at all levels of PEMFC design. Accelerated stress testing tracked by in situ X-ray diffraction indicates that catalyst aging inside PEMFCs is extremely aggressive when compared to conventional RDE testing, even in the absence of faradaic currents which further accelerate the ageing. X-ray scattering tomography and operando AST measurements are shown to be a powerful platform for deconvoluting the degradation mechanisms of electrocatalysts. Stress tests performed in a liquid cell should be critically evaluated in order to predict catalyst degradation rates and mechanisms in functional systems. The presented strategy for deep, in situ and operando characterization bridging fundamental chemistry and device engineering is generally applicable to the next generation of

This work was supported by Automotive Partnership Canada and NSERC. A.V. is supported through the European Union Horizon 2020 program under Grant Agreement No. 679933 (MEMERE). The SAXS-CT was funded by Institut Carnot Energies du Futur under the STATUQUEAU project.

batteries, solar cells, and other energy conversion and storage systems with few compromises in electrochemical performance. These devices are composed of complex materials, where chemical reactivity, transport phenomena, and degradation mechanisms are intrinsically coupled, yielding heterogeneous distributions of phases. Advanced tools capable of providing real-time, multi-scale chemical and structural information are therefore invaluable towards understanding the evolution of these systems. We anticipate that such non-intrusive and holistic approaches, which combine several X-ray scattering tomography techniques, will enhance understanding of the roles, and interactions between different constituents, allowing next-generation materials to be incorporated into PEMFCs other electrochemical devices.

Supporting Information

Detailed descriptions of the sample preparation, small angle X-ray scattering, X-ray diffraction, computed tomography data analysis algorithms, 3D reconstructions, Rietveld refinement, electron microscopy, particle size analysis, X-ray spectroscopic imaging, and electrochemical characterization can be found in the Supporting Information.