Cedric Parizot
email: parizot@mmsh.univ-aix.fr

The Informal Dimensions of the Israeli Permit System of Access and Movementin the Occupied Palestinian Territories (1990-2010) Work in progress

INTRODUCTION

In the midst of the first Intifada (1987)(1988)(1989)(1990)(1991)(1992)(1993), the Israeli authorities imposed new regulations in order to control and filter Palestinians living in the West Bank and Gazaand attempting to enter Israel and EastJerusalem. These regulations aimed first at preventing individuals and groups from committing attacks on Israeli soil (Hass 2001). Second, they were used to limit the access of Palestinians to the Israeli labor market, and thus reduce the dependency of the Israeli economy on Palestinian manpower [START_REF] Kemp | Labormigration and racialisation: Labor market mechanisms and labor migration control policies in Israel[END_REF]). The permit system was later integrated into a more systematic policy aiming at separating the Israeli and Palestinian populations [START_REF] Hass | Israel"s Closure Policy: An Ineffective Strategy of Containment and Repression[END_REF]. Moreover, this system has generated complex formal and informal networks of intermediaries on which Palestinians became increasingly dependent for their mobility across the Israeli-Palestinian divide. Indeed, this control mechanism produces a double individualization of the subject. This individualization of control occurs, first, by defining the capacity of a Palestinian to obtain a permit according to a political and bio-social profiling, and second, by imposing on each Palestinian the sponsorship of an Israeli citizen. This condition makes the allocation of a permit dependent on his/her network of relationships.

Work in progress, please do not quote without the authorization of the author parizot@mmsh.univ-aix.fr

This study has two main objectives.First, by focusing on the chains of relations and interactions that develop through the process of permit allocation,I intend to identify the multiple actors that, within andoutside of the State of Israel, are directly taking part into the allocation of permits. This will allow me to better stress the heterogeneity of this control regime as well as its informal dimensions. Second, I wish to stress how the constitution of these formal and informal networks deeply affects the ways Palestinians relate to space and the location of borders in Israel-Palestine. I contend that the emergence of formal and informal networks around the allocation of movement permits fosters the duplicating of borders from the actual Israeli and Palestinians territories to reticular spaces.

My talk will be divided into three parts. In the first part, I will show thatthe mobility of Palestiniansisnot merely dependent on their varying statuses, as defined by the Israeli biosocial profiling system but also on the location of a given individual within a specific network of relations. In the second part, I shall demonstrate that this system fosters the coopting of formal and informal intermediaries on whom Palestinian permit applicants are highly dependent. Finally, I will show how this cooptation system contributes to the readjustment of the functioning of the whole Israeli permit system.

I-MOBILITY: A MATTER OF STATUS OR NETWORK?

The literature dealing with the issue of the permit systemin Israel-Palestine has mainly approached Palestinians" access to mobility as being determined strictly by their political profile and bio-social profile (age, status, occupation) (see for instance Abu [START_REF] Zahra | Legal Geographies in Palestine: Identity Documentation, Dispossession, Repression and Resistance[END_REF][START_REF] Hanieh | The Politics of Curfew in the Occupied Territories[END_REF][START_REF] Tobias | Law, Violence and Sovereignty among West Bank Palestinians[END_REF]. As a matter of fact,Israeli authorities define the restrictions imposed on Palestinian workers and individuals on the basis of age, occupation, marital status, as well as hispolitical affiliation.Yet, I"d like to show that this approach is too reductive, as it relies too much on the discourse of the Israeli authorities. In practice security and bio-social profiles are less significantthan an individual"sbelonging to a network and his/her location within it.

Three elements call into question the significance of security and bio-social profiling. First of all, bio-social profiles are often unclear. They have changed constantly since the beginning of the 1990s. While at the beginning of the 2000s only male workers older than 30 could apply for permits, this age limit was raised and later lowered again (Ekstein 2011(Ekstein , B"tselem 2007)).

Moreover, there is a certain level of arbitrariness in the way these permits are allocated. A

Work in progress, please do not quote without the authorization of the author parizot@mmsh.univ-aix.fr person fitting the official criteria and having no security record can be refused a work permit inside Israel without knowing the reasons, while a person not fitting these criteria could be allocated a permit [START_REF] Handel | Where, Where to and When in the Occupied Territories ? An Introduction to Geography of Disaster[END_REF]. In other words, it is hard for Palestinians as well as for observers to make sense of the precise definition of these profiles.

Second, regardless of his/her bio-social profile, a person wishing to obtain a permitsystematically needs to be sponsored by an Israeli citizen or a foreign body accredited Both formally and in practice the procedure of permit application makes Palestinians closely dependent on their sponsors on the Israeli side. It is the intervention of these same sponsors that can validate or eludetheir profile and thusprovide them with an access to mobility.

II-THE PERMIT SYSTEM AND THE COOPTATION OF INTERMEDIARIES

The sponsorship imposed on Palestinian permit applicants and the modes of bureaucratic circumvention introduced by the Israeli authorities have contributed to the establishment of patron/client relations between the State authorities, intermediaries and permit applicants.

Work in progress, please do not quote without the authorization of the author parizot@mmsh.univ-aix.fr

Existing literature has discussed these patron/client relations between the Israeli authorities and the Palestinian population (see for instance [START_REF] Azulay | Ce régime qui n'en est pas un: occupation et démocratie entre la mer et la rivière[END_REF]. They have underscored the fact that this system of dependence has been used extensively as a tool of control either to maintain Palestinian dependency on Israel anddeter resistance, or to recruit an extensive network of collaborators. Yet, the other implications of the emergence of such chains of intermediaries between Palestinians and the Israeli authorities have been overlooked.

This sponsorship system has also contributed to the cooptation of formal sponsors as "regulating authorities". They are held responsible for the behavior of the Palestinians they sponsor. They are also in a position to select a certain person at the expense of another. They can facilitate and accelerate the procedure, the length of the permit, the time it covers during a day, as well as the territory it may cover within Israel. This regulating role is not merely symbolic sincesponsors are the actors who are first addressed by Palestinians. It is not the Israeli Authorities that a Palestinian will practically approach to apply, but rather these sponsors, who will in turn transmit the application to the relevant administration. Finally, the complexity and the lack of transparency of the issuing procedure of permits fostered the intervention of "bridge-persons" (literally, persons that make profit out of playing a role of go-between).For example: Palestinian attorneysare often involved in order to clarify the reasons why an applicant is systematically refused a permit, or simply to accelerate the delivery. Given the tightening of movement restrictions and the lack of mobility of Palestinians these attorneys have been increasingly compelled to rely on Israeli attorneys.

Sometimes, Palestinians prefer to contact directly Israeli lawyers. Beside lawyers, many other people tend to intervene: from individuals trying to sell crucial information or contacts, to people that facilitate the waiting in lines at Israeli offices or check points….

III-MEDIATION AND THE INFORMAL ECONOMY

In other words, beyond the co-opting of an increasing number of formal and informal intermediaries into the functioning of the mobility regime, the system of sponsorship opens up new opportunities for a series of actors that have re-appropriated this permit regime to increase their power and profit.

As in many other instances in the world, the dependency of workers toward their sponsors opens the way to new articulations of power relations andpossibilities for exploitation. The way Israeli entrepreneurshave profited of this dependency of Palestinian workers within Israel proper and inside the Israeli settlements has been extensively documented and even denounced by both the academic literature and NGOs involved in the defense of human rights. But this impact should be studied further at other levels. For instance, little research has been conducted about the way this dependency has also affected power relations between churches, diplomatic agencies, NGOs and the Palestinian workers or staff they all recruit.

Work in progress, please do not quote without the authorization of the author parizot@mmsh.univ-aix.fr

From an economic point of view some Israeli and Palestinian entrepreneurs have set up very profitable activities around the informal trafficking of real permits. Israeli entrepreneurs often apply for more permits than the number they actually need. They resort to such a strategy in order to counter the potential refusal of the Israeli authorities to allocate permits to a certain number of persons. The underlying logic is that it is better to ask for more than to have an insufficient number of workers on site. If an employerhas a surplus of permits, he can always use the additional ones to help former of future employees.

Yet, other employers have deployed another strategy in order to maximize their profits.

Instead of applying for the 100 permits he needsan entrepreneur will apply for 200 for a period of 6 months to the Israeli Work Office. Once obtained, the additional permits will be sold at a higher price to Palestinian workers. In 2010, a permit which actually cost 1200 NIS (240€) to an entrepreneur per month could be sold up to 1800NIS (360€).The sale of 100 sixmonth-permits would thus represent a profit amounting to 360 000NIS (72 000€)! The Palestinian workers who would benefit from this sponsoring would be able to cross checkpoints "legally" and evolve in Israel more or less freely.Yet, they would have to find a job by themselves… "illegally".

Such a trade cannot occur without a complex and wide chain of informal intermediaries,sincepermits are only issued by the Israeli Authorities and applications need to refer to the exact details of the Palestinian worker (ID card number, magnet number, etc.)and involve workers that are not supposed to be rejected by the General Security Services.So, an Israeli entrepreneur involved in such an informal-formal trade needs to rely, on the Palestinian side, on a contact or a chain of contacts which he can trustenough in order to obtain such information and broaden the spectrum of his clients. Moreover, pursued on a large scale, as some have done, such a trade needs to involve consultants (accountants, lawyers, etc.) who could help to set up the business by issuing fake orders, contracts and bills, as well as byjustifying the profit generated by such an activity to the Israeli tax office. Some networks have actuallyinvolved high-ranking Israeli civil servants within the Israeli Ministry of Interior and the Civil Administration, to the point that they have been able, in certain years,to exceed the quotas of permits!

The development of these activities is such that there is indeed a parallel network of permit allocation between Israel and the Occupied Territory. In the southern West Bank people

Work in progress, please do not quote without the authorization of the author parizot@mmsh.univ-aix.fr would tell me that there are four main ways to obtain a permit: the official channel through an Israeli entrepreneur; a real permitobtained through a fake sponsorship (more expensive); a permit obtained through a Palestinian collaborating with the Israeli GSS; and a fake permit obtained through a falsifier.

Needless to say that the wealth and the power that can be obtained through thesenetworks push the people who master them to regulate the entry of outsiders.As a matter of fact, not everybody can access these networks of facilitators or of permit traffickers. The rules and limitations filtering the entryof people intosuch networks contribute to the building of new obstacles to movement.Since these obstacles affect levels of connections and interactions they cannot be defined as borders. Nevertheless, they render territorial or topographical borders more impermeable as, in order to obtain a permit that allows one to cross the territorial limits imposed by Israel, Palestinians first have to circumvent or pass through topological obstacles within these networks.

CONCLUSION

The study of the Israeli permit system,as seen from the point of viewof the formal and informal networks it generates,allows us a unique perspective on its functioning.

  by the Israeli authorities. For instance, a Palestinian worker desiringto work in Israel will turn to his Israeli employer to get a permit. The employer will then apply to the Israeli Work office by providing the precise details of his Palestinian worker (ID number, name, etc.). The application will then be transmitted by the Work office to the Israeli General Security Services (GSS). If the lattervalidate it, they will allow the Work Office to issue a work permit to the Israeli entrepreneur and the Palestinian worker. Many other sponsors can also be summoned. According to one"s occupation and activity within Israel he or she could contact clergy members belonging to different churches in Jerusalem; members ofdiplomatic representations, NGO, etc.In practice, networks are more influential than status. Anunfitting security and bio-social profile of a Palestinian is often overlooked by the authorities if thePalestinian applicant or his sponsoris willing to cooperate with a person linked to the GSS. Moreover, Israeli authorities have long ago accepted certain modes of circumventing the length of the procedures. Israeli civil servants, Member of the Knesset Israeli Parliament, or lawyerscan accelerate the procedure of application and delivery of a work permit to a Palestinian that enjoys their direct or indirect support.

Furthermore, this system

  of sponsorship has contributed to the co-opting of informal intermediaries whose number has increased between the 1990s and 2000s as a result of the degradation of the politicalsituation between Israelis and Palestinians. Since the outburst of the second Intifada, more intermediaries have been needed to ensure contacts between Palestinians workers and their Israeli employers. In 2000 Israelis citizens wereformally forbidden by Israeli authorities to enter Palestinian autonomous areas in the West Bank and Gaza (see map on ppt.). Moreover, given the rising number of attacks many Israeli employers dread to enterthe occupied territories.Consequently, in order to recruit workers and to ensure their transportation to the working site Israeli employershave been compelled to rely on new intermediaries who can be eitherPalestinians holding Israeli citizenship or Palestinians living in the Occupied Territories. These gobetweens have helped to recruit the workers as well as to ensure theircoaching on Israeli working sites. Moreover, informal go-betweens have been appointed by the Israeli authorities.Since the outburst of the second Intifada (2000) and the rupture of the security cooperation in 2002, the Israeli Coordination office in the Occupied Territory has ceased to work with the Palestinian Work in progress, please do not quote without the authorization of the author parizot@mmsh.univ-aix.fr Coordination office. Between 1994and 2000Palestiniansneeding a permit could pass through the mediation of the Palestinian coordination office whowould transfer their application to the Israeli coordination office. Since the outbreak of the second Intifada, the Israeli coordination office has allowed parallel channels and bodies within the Palestinian National Authority, such as municipalities, ministry civil servants, governorates, chambers of commerce, etc.,to transfer permits applications

  First, going beyond the institutional definition of this control mechanism helps identifying the many actors that participate in it. These includeIsraelis and Palestinians actors, State and non State actors, local and internationals, formal and informal actors. Moreover, the network approach allows a better understanding of the economy of relations deployed within this power mechanism. It shows the way the Israeli State delegates its control toformal and informal intermediaries that have become, at different scales, new "regulating authorities" of Palestinian movement. It also highlights how this mechanism is diverted, by different actors, to achieveeconomic and political goals and the way their daily participation affects in turn the functioning of the whole mechanism of surveillance. Furthermore, a network approachalso helps us to better apprehend how the individualization of control duplicatesor extends borders within reticular spaces. Since it favors the emergence of networks, within which connections are regulated, exchangedagainst specific payment, the permit regime has duplicated borders by creating new topological limits: each connection becomes a potential obstacle. These informal limits are not mere metaphors; they are very real and substantialfor Palestinians who need to obtain a permit. They come first, i.e. it is only

Work in progress, please do not quote without the authorization of the author parizot@mmsh.univ-aix.fr PortugaliJuval. 1989. "Nomad labor: theory and practice in the Israeli-Palestinian case".

Transactions of the Institute of British Geographers, 14(2): 207-220.


Cédric Parizot
email: cedric.parizot@gmail.com

DIPLOMATS, EXPATS AND THE ISRAELI MOBILITY REGIME Who Maintains Jerusalem Borders?

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

INTRODUCTION

This talk presents the beginning of a study on themanagement of Jerusalem entry permits by foreign consulatesduring the post Intifada period (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013). Since they are regularly welcoming into their offices Palestinians from the West Bank and Gaza, foreign consulates do apply recurrently for Jerusalem entry permits to the Israeli COGAT1 . Through this analysis, I wishto assess the role of these foreign institutions in maintaining the bordersunilaterally imposed by Israel around the city.

As Mick Dumper argues in his recent book, the "international interests and involvement in Jerusalem both constrains the assertion of sovereignty, whether it be Israeli or Palestinian, and consolidates the ambiguity over current borders (Dumper 2014, 156)". I fully agree with this assertion as long as borders are seen from a territorial perspective, i.e. as geographical boundaries setting the official limits of State sovereignty. Yet, the relation between the local international representationsand Jerusalem boundaries is very different if one approachesthese borders through their functioning, i.e. as networks and flows of control operations that aim to filter and channel flows of goods and people [START_REF] Bigo | Frontières, territoire, sécurité, souveraineté[END_REF].

From this second angle, foreign consulates appear to be very much involved in themaintaining of Jerusalem borders since they act as recurrent mediators within the permit regime. Of course, this does not mean that they participate voluntarily or support the Israeli policy of separation. On the contrary, at individual level, many Jerusalem diplomats and consulate employees attempt toresist it. In order to challenge the exclusion of West Bank and Gaza Palestinians, manystrive toincrease the number of issues of entry permits.While these scattered actions do punctually help certain people, theircumulative effects actions are yet to be assessed. This is what I would like to do in this presentation. I will assess to what extent foreign consulates fit into the Israeli administrative machinery and affect its functioning. I will apprehend the interactions between them and the Israeli institutions in charge of the permit regime through the metaphor of the assemblagedefined by Deleuze and Guattari and recently summarized by [START_REF] Delanda | A new Philosophy of Society, Assemblage Theory and Social Complexity[END_REF] 2 . This means that I will focus on the capacity of these different institutions to articulate one another through relationships of exteriority and to maintain a powerful system of control, rather than on the interaction and the confrontation between theircontrasting internal logics and properties. An assemblage is constituted by heterogeneous, autonomous and self-subsistent parts whose logics and interests contrast sharply but whose articulation generates powerful effects and processes. Here, I will argue that despite their strong motivations, skills and effortsto alleviate Palestinian suffering, as a whole,foreign consulatescontribute toreinforce the Israeli mobility regime and the spaces of differentiated and negotiated circulation that it creates around Jerusalem. I will divide my talk into three parts : first, I will show how much the management of Palestinian permit applications mobilizes foreign consulates located in Jerusalem ; second, I will analyze how these practices integrate these foreign institutions in the heart of the Israeli administrative machinery and increase the complexity of the Israeli bordernetwork ; finally, I will assess the cumulative effects of theseprocesses on the lives of the Palestinians and on their perceptions of the Israeli control system.

I-JERUSALEM CONSULATES AND THE ISRAELI PERMIT SYSTEM

The involvement of Jerusalem consulates in the Israeli mobility regime can be assessed through the numbers and the kinds of permits they obtain on behalf of Palestinians entering the limits of the city. It can also be measured by theinternal administrative reorganization that the management of these procedures implies.

A) Jerusalem entry permits

The majority of entry permits requested by consulates are short-term visiting permits. Consulates are regularlysollicitedby West Bank and Gaza Palestinians holding the citizenship of the State these consulates represent.For instance, French-Palestinians regularly ask the French consulate general for a permit in order to accessits offices in Jerusalem and fulfill administrative procedures. These procedures can consist in registration of child birth, marriage, renewal of passport or ID cards, application for pension rights, etc. For the French consulate general, thiskind of permit applications amounts to hundreds of people each year.

In addition to this, since they play the role of informal embassies of their countries to the Palestinian National Authority, Jerusalem consulates develop numerous forms of cooperation with Palestinian national institutions, NGOs and local economic, social and cultural partners. This cooperationoften implies the organization of meetings inside Jerusalem between delegations from their country and local Palestinian representatives. Cultural and academic events can also require the invitation of Palestinian scholars and artists. Last but not least, the celebration of national holydays can mobilizenumerous Palestinian representatives, notables and guests from the West Bank and the Gaza Strip. These different kinds of activities also necessitate dozens of short term permits each year.

In contrast, work permits concern onlya small proportion of applications. While many of these consulates employ Palestinians blue and white collars who are living beyond the boundaries of the city, these employees are not the majority of their staff.

At thelevel of each consulate, the number of applications would vary from a few hundred to a few thousand each year. If one takes into account all the consulates located in Jerusalem, the local branches of international agencies such as the UN and the EU, as well as the main international NGOs, the number of applications for short and long term permitscould concern a significant amount of Palestinians. Interestingly no figures are published by the Israeli and Palestinian authorities in this respect.

B) Organizing jobs, administrative units, logistics

Given the amount of applications, some consulates create specific jobs or administrative units to deal with this procedure. Yet, the attribution of the management of permit delivery a given unit or person is a matter of a bricolage performed in order to adapt to the Israeli control system. People recruited for this job are not trained for it and their profile often corresponds tothat of a secretary. For instance, Simon, a 25-year old man, was employed by one of the consulatesgeneral in Jerusalem between 2010 and 2013. He was recruited by chance through the network of relations of local diplomats. He succeeded another employee, an Israeli with dual citizenship, who was fluent in Hebrew and had occupied this positionfor three years. More than a third of Simon's full-time job was mobilized by the management of Jerusalem entry permits.

Simon's job consisted incentralizing the applications emanating from diplomats and other employees of the consulate on behalf of West Bank and Gaza Palestinians. He was also requested to renew the work permits of some consulate employeesregularly. After the validation of his hierarchy he would prepare these applications by filling in special forms and send them to the COGAT of Beit El for West Bankers and to that of Erez for Gazans.

The delivery of permits to Palestinian applicants also requires the organization of a logistic chain relying on additional individuals and infrastructures. Consulate drivers have to be sent to the COGAT offices to collect the permits and, later, deliver them to the places where Palestinian applicants can retrieve them. In that respect, the level and the modes of organization vary greatly from one consulate to another. While certain consulates have many branches and staff disseminated within the OPT, like the French Institutfrançais (cultural centers) and its affiliate officesin Nablus, Ramallah and Gaza city, others would rely on much more modest means. The chain of institutionsand people that a specific consulate mobilizes also varies greatly over time.

II -FOREIGN CONSULATES AND THE ISRAELI BORDER NETWORK

This participationin the permit regimeintegrates foreign consulates in Jerusalem into the Israeli bordernetwork, i.e. the network of infrastructures and actors that implement the control, selection and filtering of Palestinian mobility.Moreover, it affects its very shape.

A) Parts of the administrative machinery

From an administrative point of view, foreign consulates arede facto recognized by the Israeli authorities as legitimateinstitutions that can act as guarantorsfor Palestinian applicants. Moreover, since they are in charge of relaying these applications to the COGAT, they are appointedas legitimate elements of the Israeli administrative machinery. Besides, this acknowledgment is formalized by the definition of specific procedures and time schedules for applications on behalf of Palestinians.

In that respect, consulates have become part of a wider system in which the Israeli authorities delegate part of the selection and the filtering of Palestinian applicants to a network of other Israeli, Palestinians and foreign actors. Consulates stand at the same level of Israeli private firmswhich regularly employ Palestinian workers. They also play a similar role to the many Palestinian intermediaries that have been integrated into this network since the start of the second Intifada.

Until 2000, the PNA was the main intermediary through which Palestinians had to apply for permits. Yet, when Israel decide to stop, for a couple of years, the security cooperation between the PNA and its institutions authorities, Israel has authorized many others interlocutors to intercede on behalf of Palestinian applicants. Within Palestinians enclaves, selected municipalities, chambers of commerce, or attorney offices have been appointed as legitimate relays of Palestinian applicants.

B) Introducing additional procedures and mediation channels

While consulates have to conform to the requirements of the COGAT when sending applications on behalf of Palestinians, they also introduce their ownmodes of functioning within this regulation network.

First, they defineautonomously the procedures that regulate the way Palestinians should apply for their sponsorship. They define the relevant people among their staff member who are entitled to receive theseapplications (diplomats, cultural attachés, honorary consuls, etc.) and later transfer them to the person in charge of contacting the COGAT. Each consulate will also define what are the legitimate reasons to justify their sponsorship.

Second, consulates setup parallel,and sometimes complex, channelsof mediation between Palestinians applicants and Israeli authorities that shortcut the COGAT. When an application concerns an important Palestinian representative, the Consul directly turns to the head of the COGAT or to other influentialfigures in the Israeli administration. Some consulates choose more complex ways of interventions. Since they are representing the interest of their country to the PNA, they consider that they do not have to interact directly with Israeli officials. So, they send a diplomatic telegram to the Foreign Ministry of their country, asking to formally request the Embassy in Tel Aviv to intercede with and put pressure on higher Israeli administrative or political bodies.

Given the consulates'uneven organizational capacities, their contrasting procedures of sponsorship and their different reaction times, their interventions reintroduce new sources of differentiated mobility between Palestinians. While some Palestinians holding a dual citizenship can count on the backing of their consular representatives, others cannot. A French-Palestinian or an American-Palestinian might enjoy better mobility across Jerusalem boundaries than a Palestinian with the citizenship of a State that does not have a consulate in Jerusalem. These discrepancies potentially hierarchize Palestinians holding dual citizenship according to the country they are affiliated to.

C) Extending the ramifications of the Israeli Border Network

Finally, the integration of foreign consulates into the Israeli mobility regime adds new material ramificationsto the Israeli border network.

This border network already encompasses multiple places and bodies. There are first the Israeli State infrastructures deployed throughout the West Bank (check points, watch towers, road blocks, indepth barriers, the Wall), as well as the Israeli institutions such as the local offices of the DCO, those of the General security services, the Civil Administration, and the different ministries. One should also add non-State actors such as the private security companies manning the checkpoints (Havkin 2011). Moreover, since the second Intifada, it also embraces many different Palestinian administrations and bodies (Parizot 2011).Foreign consulates and their local branches in the West Bank and Gaza contribute to widen this web of institutions, because they define additional sites of control and of filtering operations through which Palestinians have to navigate before and after obtaining an entry permit into Jerusalem.

In sum, the integration of foreign consulates into the Israeli permit regime reinforces the diffuse and reticular character of Israeli-Palestinian boundaries.In this realm, boundaries cannot be considered as lines or envelopes, but rather as successive and sometimes repetitive operations of control. While they are defined to filter the entry of Palestinians into Jerusalem, these operations extend far beyond the limits of the Israeli municipality and the Wall's route. They reach deep into the heart of Palestinian enclaves in order to allot differentiated degrees and modes of mobility to Palestinian applicants.Often, these operations of control are detached from their targets. This is the case when Palestinian applications are successively treated and filtered on different sites by foreign diplomats, consular secretaries, and of course the COGAT and GSS officers, and this, even before Palestinian applicants cross Jerusalem's geographical boundaries.

III -UNCERTAINTY, FRUSTRATIONS AND ARBITRARINESS

The impact ofthe foreign consulates'participation in the Israeli mobility regime is even more striking if one assesses it from the perspective of the Palestinians'life experiences.While many Jerusalembased diplomats see their efforts to secure permits for their Palestinian partners as ways of subverting the Israeli occupation and alleviating Palestinian suffering, they actually contribute indirectly to increase the level of uncertainty, violence and arbitrariness of this system.

A) Uncertainty

Palestinians are very much looking for the backing that diplomats or certain consulate employees can offer them. They are also very pleased to see the energy that some of these foreigners deploy in order to facilitate their movements across Jerusalem borders.

Yet, they regard this bridging capacity as rather uncertain and difficult to secure. This is due to the fact that Palestinians do not live in the same temporality as foreign diplomats: they spend their lives in the West Bank and Gaza while diplomats usually stay for two to four years only. It is theconstant turnover of foreign diplomats that introduces an uncertainty that is difficult to overcome even for people endowed with a high social capital and skills.

The time is 2007. Ahmad Ga'ud is a Palestinian academic from Hebron who has obtained his PhD from the universityX. By chance, a friend of his, Antony Schmit, has been appointed as vice Consul in the consulate Y in Jerusalem. Ahmad had met Antony while he was preparing his PhD in the city where Antony's parentslive. In 2007, Ahmad experienced difficulties to obtain a permit to enter Jerusalem. After several failed attempts, he contacted Antony who interceded indirectly with high Israeli representatives and succeeded in obtaining a permit for his Palestinian friend. Thanks to Antony, Ahmad enjoyed for a few years a privileged access to mobility. He was able to visit the city where he was born, something that had been denied to him since 1993.

Yet, two years later, Antony Schmit finished his term at the X consulate in Jerusalem and moved back home with his family. Ahmad Ga'ud was introduced to his successor and invested a lot of time and energy to construct a friendly relationship with him. But he never managed to reach the same level ofprotection. Moreover, he quickly realized that Antony's successor was not as skillful or motivated as his good friend. Hence, the young Palestinian academic who had briefly enjoyed the same status as some Palestinian VIPsfellback again to the level of other Palestinians, i.e. became confinedwithin the narrow limits of the West Bank. His case is no exception, but rather the rule.

B) A shadow theater

The ambiguous effects of the foreign consulates' participation in the Israeli mobility regime can finally be assessed through the informal economy it contributes to generate.Many informal intermediaries attempt to capitalize on the access they have to consular employees and diplomats.

Given the scarcity of entry permits into Israel and Jerusalem, any information or contact that can facilitate the access to consulate staff becomes a negotiable commodity.

For many,this privileged access is a source of cash. In 2009, I was asked how much I wanted for helping a friend of mine approach the French consulate employee to whom he could submit a visa application. When I expressed my surprise to him, I was told that it was normal to reward such help. His cousin, who was holding a Norwegian passport, told me that he did it quite frequently.

For others, contacts with diplomats are a source of power and prestige. As a matter of facts, it can radically affect one's relationship with his/her surroundings. It still happens to me, and I can easily identify the people who cultivate their relationships with me knowing that I would be potentially useful in the futureto them or to others. It also goes the other way around. Because certain diplomats or consulate employees know how much people wish to establish a relationship with them, they play on their interlocutors' expectations in order to win certain services or help.

Consulate staff can capitalize on such expectations all the more since people often have little information about their work, positionsand actual competences. In 2004, in Gaza, an employee of the local branch of the consulate of S was relying on such a lack of information to present himself as the local vice consul. He claimed that he was the one able to select the applicants who would receive a Visa from his consulate. Actually, he was only a secretary who was preparing applicants' files that would be later examined by other consular employees. Thanks to his talent and the symbolic capital he earned from his efforts, he extended his network of relationship and clients.

Such informal transactions and manipulations often create power relations, conflicts and frustrations. Hence this informal economy of mediation reinforces the feelings of injustice, arbitrariness and uncertainty. It strengthens a system within which the freedom of movement is seen as the exception and confinement as the rule.

Coordination for Government Activities in the Territories

I owe Christophe Sohn this idea.


Francisco Gamboa Quintanilla
email: francisco.gamboa@irccyn.ec-nantes.fr

Sylvain Kubler
email: sylvain.kubler@cran.uhp-nancy.fr

Olivier Cardin
email: olivier.cardin@irccyn.ec-nantes.fr

Pierre Castagna
email: pierre.castagna@irccyn.ec-nantes.fr

Sylvain

Product Specification in a Service-Oriented Holonic Manufacturing System using Petri-Nets

Keywords: Petri-nets, Holonic Manufacturing System, Mass Customization, Service Oriented Architecture, Manufacturing Recipe. 

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

INTRODUCTION

Mass customization (MC) refers to a business strategy that combines two different business practices: mass production and craft production. The MC concept is relatively fresh in international business, first discussed by [START_REF] Davis | Future Perfect[END_REF]. Its development lagged behind because customer needs did not have effective means, i.e. technology, to be expressed and reached by product and service manufacturers. In the recent decade, changing economic and social environments gave the push for the demands of individualized products and services. Companies are now becoming more and more customercentric. The major objective of MC is to improve the ability of companies to react faster to changing customers' needs and to address the heterogeneity of demand more efficiently. Nonetheless, the MC concept requires new approaches due to the small volume/high variety order management and the maximization of the profitability of the firms [START_REF] Blanc | A holonic approach for manufacturing execution system design: An industrial application[END_REF]. (Molina et al., 2005) argue in this sense that the next generation manufacturing systems must therefore be able to provide increased levels of flexibility, re-configurability and intelligence to allow them to respond to product variety. These concerns are challenging the Intelligent Manufacturing Systems (IMS) community from two decades, through a worldwide industry-led research aiming at setting into practice agile Business to Manufacturing systems based on a networked heterarchy of autonomous units. This type of organization appears as more suitable to meet robustness to disturbances, adaptability to rapid changes and efficient use of available resources, which are still weak points of conventional manufacturing systems [START_REF] Morel | Editorial of special issue[END_REF]. The difficulty is to combine the ability and the capacity to communicate of these units so that they can interact by creating and executing manufacturing plans to process both physical and informational customized goods. A way to express this challenge is to combine the Multi Agents System (MAS) paradigm with the Holonic Manufacturing Systems (HMS) paradigm [START_REF] Valckenaers | Special issue on intelligent manufacturing systems[END_REF]. Recent years have witnessed many proposals [START_REF] Babiceanu | Development and applications of holonic manufacturing systems: a survey[END_REF]. These paradigms require giving abilities to the products to interact with their environments such as data storage or decisionmaking abilities (e.g. products may achieve their own routing/re-routing through the supply chain) [START_REF] Sallez | A stigmergic approach for dynamic routing of active products in FMS[END_REF].

Based on these concepts, this paper explores an approach using product family design in order to generate a feasible production process based on a process description allowing multiple variants. Section 2 introduces product and process family designs. Section 3 introduces the notion of services adapted to manufacturing systems. Finally, section 4 presents the main proposal to use Petri-Nets in order to represent product recipes, and its application to a simple study case.

MANUFACTURING PRODUCT SPECIFICATION

Product Customization

The main objective of product customization is to increase a company's product variety offer as to increase its attractiveness and therefore sales. A first step is to define the product offering's customization level. For the context Product Driven Production Systems (PDS), two types of customization will be considered: scalable and modular.

Scalable customization creates variants by varying the capacity of a certain quantifiable product feature [START_REF] Simpson | Product platform design: Method and application[END_REF] e.g. a computer's hard disk capacity. Modular customization, on the other hand, creates variants through the configuration of existing modules (Meyer et al., 1997b) which are structural features of the product. As a result of product customization, product variety increases. Unfortunately, as product variety increases the law of diminishing returns means the benefits obtained in terms of sales do not keep pace. This is due to an increase of internal complexity [START_REF] Child | Sloan Management Review[END_REF]. Such problem implies a variety management issue that companies must cope by optimizing its external variety with respect to the internal complexity resulting from product differentiation. [START_REF] Tseng | Design for mass customization[END_REF] As a solution to this complexity problem and to achieve economy of scale, product families' development has been well recognized and adapted by companies as a means to optimize internal complexity and external variety (Meyer et al., 1997a). Added to this, product family design recognizes the existence of scalable and configurable product family platforms [START_REF] Jiao | Product family design and platform-based product development: a state-of-the-art review[END_REF] which adapt properly to the level of customization addressed in this paper.

Product Families

According to [START_REF] Suh | Axiomatic design: Advances and applications[END_REF], Product Family Data design encompasses five design domains. Fig. 1 presents the fundamental issues encountered while designing product families [START_REF] Suh | Axiomatic design: Advances and applications[END_REF]. The first stages of product family design, from customer needs identification all the way up to the design parameters, correspond to activities out of the scope of this paper. However, this paper addresses particularly the back-end issues corresponding to the process and logistics domains. The former refers to the design of processes and their respective variables for the realization of the Design Parameters (DPs). The later domain covers the production logistics aspects i.e. production chain configuration, resource allocation, etc. An approach will be proposed for the mapping of DPs, into the manufacturing domain (process + logistics domains) in a form that will facilitate the exploration of all production alternatives for the realization of a derived family member.

Product family refers to a set of individual products that share a set of common structural characteristics and yet are differentiated one another by certain specific features (Meyer et al., 1997b). Each of these individual products, derived from a product family, is referred as a product variant or product family instance. Product families are based on the commonality that exists between the product variants that can be derived from them. It is this communality that entails the difference between the architecture of product families from that of a single product. On the other hand it is modularity that allows the characterization of product variants. Through modularity, product structures/architectures can be split into modules. Such modules, representing physical or conceptual grouping of components sharing some characteristics, can then be used as building blocks to form a product respecting certain architectural rules. What is important in characterizing modularity in product families is the interaction among modules. This means that, for their modular aspect to be feasible, there is a need of integrity among modules. Such integrity refers to the standardization of module interfaces and the specification of architectural rules within the product platform. Fig. 1. Holistic view of product family design and development [START_REF] Suh | Axiomatic design: Advances and applications[END_REF].

In summary, product variants are constituted of a collection of modules representing structural features with a certain configuration according to product architectural rules. Such rules are implicitly defined by the modules' interfaces. It is the principle of reutilization of proven and standardized elements/modules that engenders significant benefits to companies such as: reduction in component inventory, ease on component type handling, reduced development risks and faster development time [START_REF] Fisher | Component sharing in the management of product variety: A study of automotive braking systems[END_REF].

Process Families

According to the ideas presented in [START_REF] Martinez | Product family manufacturing plan generation and classification[END_REF] and [START_REF] Schierholt | Process configuration: Combining the principles of product configuration and process planning[END_REF], the similarity found in the products' structure translates into a similarity of operations, processes and sequences among the different product family members. Thus, a common product structure and a common process structure exist within a product family data [START_REF] Jiao | Product family design and platform-based product development: a state-of-the-art review[END_REF]. This common process structure will be referred as a process family. Process families possess the same characteristics/attributes as product families in terms of commonality, modularity, reutilization and scalability [START_REF] Jiao | Product family design and platform-based product development: a state-of-the-art review[END_REF] (Meyer et al 1997a) [START_REF] Simpson | Product platform design: Method and application[END_REF]. A process family is therefore a collection of manufacturing tasks that respond to the realization of the corresponding feature modules of the product modular architecture. By decoupling the production process of a certain product variant into manufacturing tasks and relating those tasks to the corresponding structural modules of product families the reutilization principle can be then translated to the process domain. Such manufacturing tasks can be standardized and reutilized for the production of other products giving the following advantages:

• Enhanced responsiveness. Faster time to production once the product is developed as the required manufacturing tasks realizing the existing product features are already available and validated.. • Reduction in process variety due to manufacturing tasks reutilization.

• The decoupling of the manufacturing process allows the option of sequence reconfiguration which can be exploited by the production control system.

Product Modelling

Product family data design comprises several challenges. First, the organization of product data, instead of being a collection of individual product variants should explicate the relationships between the variants. Second, an individual product variant should be defined in terms of the parameters of the product family data [START_REF] Jiao | Product Family Modeling for Mass Customization[END_REF]. This last means that the generation of the specific description of a product variant is a function of both a customer specification and a product family description [START_REF] Jiao | Product Family Modeling for Mass Customization[END_REF]. The manufacturing model of a specific product family type, i.e. process family type, presented above, represents all the necessary information for the manufacture of a product in a given production platform. This model is a direct mapping of the information defined by the product model of the ISA SP-95 norm and was divided in three elements.

• Product Parameter: represents a variable that will be derived from the customization process. This parameter corresponds to a process variable derived from the customization choices made in the physical domain. According to its cardinality a product might have no or several parameters to be defined according to the level of customization attributed. These introduce the scalable character into the process domain. • Manufacturing-Service (M-Ser): Represents a manufacturing task module resulting from the mapping of a product structural feature into the process domain. They correspond to descriptions of manufacturing capabilities with no regard to the methods for their implementation.

• Service

Interdependencies/Service Recipe: Information explicating the relation and interdependencies among the different M-Sers that comprises a process family (i.e. a product family). It defines the precedence rules between the M-Ser Modules for the orchestration of production workflows. Its cardinality includes zero considering the possibility of an uncoupled production process represented by a single M-Ser, hence no need for precedence.

There exist three important relations in the model: the dependency (or use case) relation between parameter and the M-Ser, the auto-aggregation relation of the product family and the relation between the service interdependencies class and the M-Ser class. The dependency relation indicates that each of the parameters is linked to a M-Ser as to complete its specification for execution. The auto-aggregation relation suggests the possibility of the composition of a product by various sub-products that can have themselves a product model specification declared in the system. Finally there is the relation between the interdependencies class and the M-Ser class which indicates that the interdependencies class defines the relations between the different M-Sers with a certain type of formalism/methodology. Moreover, the parameter type class, besides having an identification, also contains a range of permissible values or choices for its instance. Up to now, the M-Ser Interdependencies are considered to be proprietary of the process family to which they belong and defined by the process family designer, and not as properties of the M-Sers themselves.

In short, product differentiation is achieved by both the specification of product parameters and the configuration of the different M-Ser modules by their addition, subtraction and/or substitution. It is the instantiation of each of the three elements that completely determines the production information required for the realization of a product variant. Such specification is independent of the production platform as the M-Sers are mere descriptions of the manufacturing tasks with no regard of the resources or methods implementing them. This quality makes the manufacturing product specification compatible with all types of resource models as long as they can provide the required manufacturing services. In this way, this manufacturing model contains the process family description through the collection of M-Sers and their interdependencies as well as the customer specification through the collection of parameters and the M-Sers modules selected (in case of modular choices).

MANUFACTURING SERVICES

Concept of services

As presented on section 2, the proposed product specification is based on the structural repeatability and reusability in product families. As it was mentioned, process families map the products' structural components into manufacturing process modules shared between products. In this way a bank of standardized manufacturing process modules can be created for their further reutilization given the case of an existing commonality with other process families in the same way as for structural modules in product families.

In software development, SoA (Norihisa,2006) standing for Service oriented Architecture, is a decentralized architecture that decomposes computational process into sub-processes for later distribute these among the different treatment resources available tacking advantage of their capabilities as well as of the inherent parallelism of the process. The functions treating these sub-processes are called services. According to the definition found in (Grönoos, 2001), a service is a single activity or a series of activities of a more or less intangible nature that normally takes place in the interactions between costumer and service provider, provided as a solution to achieve the customer's desired end results. SoA, within its principles, also considers the possible orchestration of different service sequences. This is of great use in the context of PDSs as they normally comprehend multiple process alternatives i.e. different workflow orchestrations. In HMS this means, more than one Resource Holon (RH) can execute one same manufacturing task and more than one workflow can produce the same product. Moreover, RHs providing the same services not necessarily use the same technology i.e. different internal models. RHs are the virtual representations of one (group of) machine(s) for which manufacturing functions have been preprogrammed according to their internal model and technologies.

By adopting the concept of services and SoA's principles, the manufacturing modules can be represented in the form of services, having a proper identification and description, which thanks to their modularity can be orchestrated in different ways thus giving a higher level of flexibility to the system. In this way, the resources' capability is delimited by the catalogue of manufacturing services (M-Ser) that they offer to the system, based on the tasks' nature itself, rather than on the identification of a specific function proprietary to the resource that has to be known a priori during process design. Thus, integrating services facilitates the integration of new resources and a process design independent from the production platform knowledge.

Manufacturing services modelling

Translating the concept of services to the manufacturing context gives rise to a specific type of service: the Manufacturing Service (M-Ser) which in turn needs of a specific model. Fig. 3 shows the model of a M-Ser conceived to welcome product customization. Like it is illustrated, a M-Ser is composed of two main elements (classes):

• Operation: represents the activity related to the M-Ser. From the consumer perspective: descriptions of the transformations made on the product. From the provider's perspective: the function with the algorithms that execute the M-Ser. Such algorithms are dependent of the resource's technology and are proprietary to the RH providing it. Therefore, the operation type is unique to the service customers but there can exist different instances that are internal to the provider RH and that are not visible to the rest of the system. Each M-Ser has one single operation class as it's cardinality shows, i.e. there is no need to declare more than one function for the execution of a M-Ser. Examples of operation types are: {perforate, paint, weld, etc.} which need of some parameters specification. • Parameter: It can come in two forms: variables or materials. In the former case, it represents a variable with a range of permissible values corresponding to a design parameter from the physical domain during customization e.g. Element X position in x coordinate = {0 -10} cm or {0, 2, 4, 6, 8, 10} cm. In the latter case, they indicate the category of the component to be added to the main product by the operation. The selection of the material or sub product is done inside a range of component variants of the same category, e.g. Category: Hard Disk, Range: {200Gb, 300Gb, 400Gb,1Tb}. Its cardinality indicates that a M-Ser can comprise zero or more parameters depending of its flexibility level to reproduce different results out of the same operation function. (Grönoos, 2001) definition implies that a service can be itself composed of other more granular services. Such services are referred as Compound Manufacturing Services (CM-Ser). Such relation can be seen as indirect auto-aggregation done thought the operation class. The question still remaining is: why not better make a direct auto-aggregation of the MSer class with itself? The reason is that the content of the operation class, from the provider's perspective, depends on the provider's internal model and not on the service definition itself. Hence, one same M-Ser provided by different RHs can be considered either as a single service or as a compound service depending on the RH providing it. It might be the case that the RH could implement an internal holonic platform to provide a M-Ser by the orchestration of more granular services instead of a single hard programmed function. It is precisely the decoupling of parameters from operation that allows bringing product customization to the manufacturing domain. Therefore, as product customization is based on the reutilization of structural features, the M-Sers used to produce such features can be adapted to the different products variants and/or families through service parameterization. The group of Manufacturing Services that can be derived from this model can be seen as a family sharing a same operation description but differentiated by the values in their parameterization. In this way, the instance of a manufacturing service type will be issued from the instantiation of the Parameters Type class which is in turn determined by product customization.

Manufacturing

MODELING PROCESS FAMILIES WITH PETRI-NETS

In the context of a PDS, the methods and techniques for representing product manufacturing specification is one of the key design issues as the control of the system is based on products. Such method of representation should satisfy the following needs identified from the product manufacturing model:

• Contain all the information of the product manufacturing-model i.e. parameters, M-Sers and service interdependencies. • Capable of expressing all the possible service choreographies (workflows) that can realize the specified product. • Must facilitate the online edition of the product specification. • Must be simple to understand and to program.

• Its memory requirement must be minimal for possible embedded applications as in the implementation of intelligent products level 2 [START_REF] Wong | The Intelligent Product Driven Supply Chain[END_REF].

Petri Nets [START_REF] Murata | Petri nets: Properties, Analysis and Applications[END_REF], a well-known modelling formalism in the academic and industrial domain, turns out to be a very good candidate for this purpose. This is mainly due to its characteristic ability to capture the synchronous and asynchronous of a process in a simple manner.. Thanks to this, and to the evolution mechanisms of the formalism, petri nets have the advantageous capacity of representing a great number of sequence combinations with a single net. This is of great importance as the main goal is to design a product manufacturing informational model that allows the exploitation of the flexibility to the PDS control strategies. This flexibility should translate into the exploration of all the possible production workflows realizing a specified product. Traditionally, process design involves the implementation of static models which specify a single predefined production workflow. The use of Petri Nets has already been recognized by (Mendez et al 2010) by enriching the process model by considering the existence of different alternative services for a given production state with the objective of involving decision engines in the system. The modelling strategy presented in this paper has the intention enrich the process model, still using Petri Nets in order to increase the decision area by putting in question the ejection order of services. By fusing together the Petri-Net formalism, product family design and the concept of manufacturing services a net with the following characteristics is obtained:

• M-Sers are represented by transitions each with its identifier. Being S:T →{s1,s2,..,sn} the finite set of M-Sers associated to the corresponding transitions. • Services are expressed in the form M-Ser_id(parameters). Parameters are attributes of the M-Sers. • The production states of a product are indicated by the Nets' marking. Such marking implicitly indicates the services that have been executed at a given point. • The service interdependencies are defined by the set of arcs connecting places and transitions and the evolution rules of the Petri-Net formalism. This information is inherently contained in the Net's structure.

To better understand the Petri-Net approach, Fig. 6 shows an illustrative example of a theoretical process family using Legos. It consists of a Lego base that will be used to represent the transporter of the product and a set of blocks each one standing for an instance of a certain M-Ser type.

The idea is to use the structural dependencies in the Lego structure to illustrate a process family structure and how this can be represented with a Petri-net. The Lego process family, Fig. 4, comprises two family members: variant 1 and variant 2. 2. Serving from the interdependencies table, the following Petri-Net structure can be derived (Fig. 5). As mentioned before, the production state of the product in question is given by the net's marking which enables the triggering of certain transitions. Thanks to this, at a certain production state, it can be known the allowed M-Sers to execute next, that will respect the M-Ser interdependencies. This allows the exploration of the alternatives given by the independence between certain services. For example, services corresponding to Legos 1 through 4 can be executed at any time in the production state as long as they haven't been made thanks to their lack of dependencies. On the other hand, Sr3 is dependent of the previous execution of both Sr1. In short, from a single Petri-Net, a state-automaton can be generated with all the possible workflows, lower memory consumption and more straight forward programming. This study case has the particularity to clearly illustrate the possible variants in manufacturing, where some operations can be performed before others without impact on the quality of the final product. Future works deal with the implementation of these nets in a Service-oriented HMS. Indeed, it is necessary to introduce new negotiation protocols between holons to be able to take into account the flexibility added by the variants in the recipes.

  Fig. 2. UML Product ManufacturingModel

Fig. 3 .

 3 Fig. 3. UML Manufacturing Service Type Model

Fig. 5 .

 5 Fig. 5. Example: Petri-Net representing the Product Manufacturing Model

Table 1 .

 1 Example: Equivalence TableOut of the Lego configuration it can be seen a series of interdependencies between the M-Sers. These interdependencies are illustrated in Table

Table 1 contains the Lego block representation of the different M-Ser types.

Fig. 4. Example: Process configuration illustration

Table 2 .

 2 Example: Manufacturing-Service interdependencies


Liselotte Tinel
email: liselotte.tinel@ircelyon.univ-lyon1.fr

Stéphane Dumas
email: stephane.dumas@univ-lyon1.fr

Christian George
email: christian.george@ircelyon.univ-lyon1.fr

A time

Keywords: laser flash photolysis, imidazole-2-carboxaldehyde, iodide, bromide, chloride, surface micro-layer, marine boundary layer

teaching and research institutions in France or abroad, or from public or private research centers.

Introduction

A significant fraction of the carbon atoms present in dissolved natural organic material bear carbonyl groups [START_REF]Humic substances in the Swannee River, Georgia: Interactions, Properties and proposed structures[END_REF]. These carbonyls, and more particularly aromatic carbonyls, are thought to be important photooxidants for various phenols present in natural waters. Aromatic ketones absorb in the natural emission spectrum of the sun and their photoactivated states react with phenols at rates close to the diffusion-controlled limit [START_REF] Foote | Free radicals in biology[END_REF]. Canonica and co-workers brought into evidence that this photooxidation involved proton or electron transfer from the triplet excited state of the carbonyl functionalities, which showed to be important oxidants despite their rather short lifetime [START_REF] Canonica | [END_REF]4]. Aromatic ketones, like benzophenone, also oxidize efficiently sea salt halides after absorption of actinic sunlight [5]. Photosensitized reactions of aromatic carbonyls are not only known oxidants in natural waters, but showed also to be an important source of hydrogen peroxide in atmospheric aerosols [6].

Imidazole-2-carboxaldehyde (IC), bearing a carbonyl function, and other imidazoles get growing interest in atmospheric chemistry, since their presence in secondary organic aerosols (SOA) has been explained by a catalytic process in situ involving ammonium salts and glyoxal, an ubiquitous organic compound in the troposphere [7,8]. This catalytic product formation in aerosols explains part of the missing glyoxal in the gas-phase through an uptake of glyoxal that was ignored for a long time [9,10]. Recently, it has been shown that imidazole-2-carboxaldehyde, one of the products formed by the 'iminium-pathway', can efficiently photo-induce the growth of aerosols [11]. This compound is thus a secondary formed photosensitizer and can play an important role in SOA growth in the absence of gas-phase oxidants under light conditions. The presence of these nitrogen containing compounds in particles can also lead to changes in the optical properties of the aerosol, hence affecting the aerosols' radiative forcing and cloud properties [12,13].

Imidazole compounds are also known to be present in the sea and at the sea surface microlayer (SML) [14,15]. Glyoxal has been measured in the marine boundary layer (MBL) [16] and amines are an important constituent of marine aerosols [17], which comforts the hypothesis of formation of imidazoles in the marine environment. The SML shows also an enrichment of nitrogen content during periods of high biological activity [START_REF] Liss | The Sea Surface and Global Change[END_REF]. The organicenriched SML, the thin interfacial zone between the atmosphere and the subsurface water, presents different chemical and physical features than the underlying water and plays an important role in the sea-air chemical interactions. Ozone loss from the marine boundary layer (MBL), for example, can occur through the reactive uptake of ozone by plant exudates such as chlorophyll present in the SML [START_REF] Clifford | [END_REF]20,21]. SML samples also feature higher absorption in UV-region than the bulk, implying that photochemical processes can be important in transformations in and between dissolved and particulate matter [START_REF] Liss | The Sea Surface and Global Change[END_REF].

Photoactive compounds, found in a higher concentration in the SML than in the underlying water, can also produce active halogen species after oxidation of the halides present in the MBL, both as aerosols and in the sea water. Photo-activated aromatic carbonyls, like benzophenone, and other photoactive compounds like chlorophyll, can lead to the formation of the reactive radical anion (X2 •-) and molecular halogens, that can be released in the gas-phase [5,22]. This kind of direct photochemical reactions at the interface could account for a part of the halides observed over open oceans [23]. Gas-phase halogen atoms, especially iodine and bromine, will set in catalytic cycles of ozone destruction in the MBL, thus changing locally the oxidizing capacities. Gas-phase iodine chemistry can also give rise to particle formation [24,25], while chlorine will be incline to oxidize hydrocarbons [26].

Other sources of such reactive halogen atoms in the MBL include photolysis of polyhalogenated compounds emitted by algae [27], heterogeneous chemistry of ozone or NOy on snow or sea-salt particles [28] and particularly for chlorine, photochemical reactions at the air-sea interface [29]. Halogen chemistry is thus profoundly entwined with the aerosol production and oxidizing strength of the MBL, affecting potentially the cloud condensation nuclei and hence climate change.

The aim of this work is to explore the photochemical properties of imidazole-2carboxaldehyde (IC), a secondary photosensitizer potentially present in the marine environment and known to induce particle growth as a secondary formed photosensitizer and to examine the bimolecular rate coefficients of this compound in presence of halide anions, Cl -, Br -and I -by means of laser flash photolysis.

Experimental

Laser flash photolysis: The transient absorption spectrum of the excited IC was followed with a classical laser flash photolysis apparatus [20]. The photolysis excitation source was the third harmonic (266 nm, pulse width ~7 ns) of a Nd:YAG laser (Surelite II 10, Continuum) operated in the single-shot mode. The choice of the wavelength is justified by the maximum of absorption of IC at 290 nm, as can be seen from the absorption spectrum shown on figure 1, even if it has been shown that at wavelengths > 290 nm, IC can induce a photosensitized reaction [11].

During the experiments, the laser pulse energy was limited at 15 mJ per pulse (~39 mJ/cm²) to limit as much as possible photolysis of the photosensitizer and therefore the possible interferences of its products on the studied chemistry, but also two photons nm, limits determined by the measuring system; for the kinetics, the probe wavelengths for the transient absorption decay of triplet state of IC were 330 nm and 350 nm.

For the analysis of triplet state decays of IC in pure water, linear regression on a logarithmic plot of the data and a mono-exponential decay model fits were performed on the same data sets. As the results of both fitting methods were comparable, we will here only present the results obtained by non-linear fits.

Materials and solutions:

All the experiments were performed at room temperature in the range 295-300 K. Aqueous solutions containing 0.25mM of IC were deoxygenated with nitrogen for 20 minutes prior to analysis and kept under a continuous stream of nitrogen during the experiment. All solutions were freshly prepared using 18MΩ ultra pure water used in this study -imidazole-2-carboxaldehyde (Aldrich, 97%), sodium chloride (>99% Sigma-Aldrich), sodium iodide (>99% Sigma-Aldrich), sodium bromide (>99% Sigma-Aldrich)were all used without further purification. The known impurity of bi-imidazole in the commercial imidazole-2-carboxaldehyde did not notably interfere, since no absorption for triplet state bi-imidazole was detected. In our conditions, aqueous solutions of pH 6.5, IC is expected to be in its aldehyde form [30].

Results

Characteristics of the triplet state imidazole-2-carboxaldehyde

Laser flash photolysis of N2-saturated solutions of 0. The absorption decay trace of excited 3 IC* at 330 nm fitted well a single exponential process of the form:

𝑦 = 𝑎 + 𝑏𝑒 -𝑡𝑘 1 (eq. 1)
over the 0-10 µs region with k1= (8.87 ±0.11) × 10 5 s -1 . The lifetime of the triplet state of IC, defined as

𝜏 = 1 𝑘 1 (eq. 2)
could thus be determined and was found to be τ =1.21 µs in a deoxygenated solution. This lifetime seems to be in accordance with a triplet state excitation, for which lifetimes are expected to be in the range of 10 -7 to 1s [START_REF]Technologie Photochimique[END_REF]. Other photosensitizers like pterin have a reported triplet state lifetime of the same order (2.3 ± 0.2 µs) [START_REF] Chahidi | [END_REF].

In presence of oxygen, the lifetime of the triplet state decreased in an oxygen saturated solution, which indicates that an energy transfer to oxygen is possible. In an air saturated solution the quenching constant for the reaction with oxygen was estimated at 3.9 x 10 9 M -1 s -1 , assuming that the concentration of oxygen is described by Henry's law. This fast energy transfer could generate reactive oxygen species such as singlet oxygen or superoxide anions.

Quenching

The reaction of 3 IC* with 3 sea salt halides i.e. chloride, bromide and iodide was investigated.

These salts are present in different and varying concentrations in the seawater (and aerosols);

the average chloride concentration is around 0.54 M, bromide concentrations around 0.84 mM and iodide varying between 0.02 µM and 0.4 µM [START_REF] Kennish | Practical handbook of marine science[END_REF][START_REF] Chang | [END_REF]. Previous studies have shown that sea salts, like phenols, can act as electron donors towards the excited carbonyls forming reactive halide radicals [4,5]. The reaction mechanism for the growth of aerosols containing traces of IC, proposed in Aregahegn et al. [11], suggests that the excited state 3 IC* can act through a proton or an electron transfer from limonene towards IC. In this study, photoactivated IC is expected to interact with the halide anions by electron transfer to produce atomic halogens [5]:

3 IC* + X -→ IC •-+ X • (E.1)
The reactivity of the three quenchers was investigated by introducing NaI, NaBr or NaCl in different concentrations in deoxygenated aqueous solutions of IC, with a large excess of the quencher towards the photosensitizer, respecting pseudo-first order conditions. The quenching rates coefficients for 3 IC* in presence of the halides were determined by the Stern-Volmer equation (eq. 3):

-

𝑑[ 𝐼𝐶 * 3 ] 𝑑𝑡 = (𝑘 0 + 𝑘 𝑞 [𝑋 -])[ 𝐼𝐶 * 3 ] = 𝑘 𝑜𝑏𝑠 [ 𝐼𝐶 * 3 ] (eq.3)
where k0 is the rate coefficient of the triplet state decay in the absence of oxygen and kq the rate coefficient for the quenching process by the halide X - [START_REF]Technologie Photochimique[END_REF]. A Stern-Volmer plot of the observed rate coefficient kobs in function of the concentration of the quencher X -permits to obtain the quenching rate coefficient kq from the slope of the curve.

Iodide

The decay of the triplet-triplet absorption monitored at 330 nm in the presence of NaI showed still a mono-exponential decay, but decreased much faster in presence of increasing concentration of I -(fig. 3). obtained is close to the diffusion controlled limit and shows that the quenching by the iodide anion is highly efficient.

Bromide

Triplet-triplet absorption decay of IC was also faster in presence of increasing concentrations of NaBr, remaining mono-exponential at 330 nm for concentrations of bromide < 200 mM.

From the Stern-Volmer plot (fig. 4), the quenching rate coefficient determined was kq(Br -)= (6.27 ± 0.53) × 10 6 M -1 s -1 for bromide. The quenching rate coefficient is orders of magnitude lower than the quenching rate for iodide and also quite slow compared to the rates obtained with other photosensitizers, such as benzophenone, where values for quenching rates for bromide are comprised between 2.2 -3.5 × 10 8 M -1 s -1 [5,[START_REF] Kennish | Practical handbook of marine science[END_REF].

Chloride

In the presence of chloride, the absorbance of 3 IC* showed only small decreased lifetimes, even with chloride concentrations up to 1 M (fig. 4). The quenching rate coefficient determined is kq(Cl -) = (1.31 ± 0.16) × 10 5 M -1 s -1 and in view of the coefficients obtained for the other halides, we can conclude that the quenching of triplet state IC by chloride is not efficient.

Comparison of the three quenchers

When considering the three quenching rate coefficients, it comes into evidence that the quenching rate coefficients are linked to the oxidation potentials of the used halides. Table 1 lists the quenching rate coefficients and the oxidation potentials for each halide. For the halide with the lowest oxidation potential, iodide, the quenching rate coefficient obtained is four orders of magnitude higher than the quenching rate coefficient obtained for chloride. It seems thus probable that the excited triplet state of IC is quenched by these halides by an electron transfer towards 3 IC*. Electron transfer from a halide (X -) to the excited triplet state of a carbonyl compound yields a halide radical and a ketyl radical.

Table I: The oxidation potential E(X -/X) of each halide and their quenching rate coefficients Kq obtained for 3 IC* Quencher E(X/X -) (V) [START_REF] Murov | Handbook of Photochemistry 2 nd edition[END_REF] kq (M -1 s - Such an intramolecular electron transfer is usually described by a mechanism, schematized in equation 2, involving the formation of a contact complex, after which the electron transfer takes place and a charge complex is formed. Finally, the charge complex breaks up and oxidized donor and reduced acceptor are separated.

3 (IC )* + X -⇄ [ 3 (IC)* ••• X -] ⇄ [ IC •-••• X • ] → IC •-+ X • (E.2)
This mechanism requires the free enthalpy of the electron transfer (ΔGET) to be negative or close to zero for the electron transfer to become thermodynamically favorable [5,35] . It could be interesting to compare the free enthalpy of the electron transfer for each quencher, if the reduction potential of IC and the energy of the triplet state of the photosensitizer were known. It seems that iodide, the halide with the lowest electronegativity, will be the best electron donor and consequently the most efficient quencher, hence the highest rate coefficient determined. Chloride on the other hand displays the highest electronegativity and oxidation potential and is a poor electron donor. The rate coefficient of the quenching with chloride was, as expected, lower than for bromide and iodide. The energy of triplet state IC is thus expected to be higher than the oxidation energy of iodide and lower than the oxidation energy of bromide, since the rate for the electron transfer from iodide is close to the diffusion limited rate but substantially lower for bromide. The electron transfer from chloride is thermodynamically unfavorable as is reflected by the very low rate coefficient.

Discussion

In the mechanism (E.2) proposed above, there is formation of halogen atom radicals. These

Iodide

As mentioned in the previous section, the decays of absorption of 3 IC* in presence of iodide could be fitted by a mono-exponential function at wavelengths around 330 nm, the maximum absorption of 3 IC*. At longer wavelengths, particularly at 380 nm, as illustrated by figure 5, the decays fitted a bi-exponential decay of the form:

𝑦 = 𝑎 + 𝑏 1 𝑒 -𝑡𝑘 1 + 𝑏 2 𝑒 -𝑡𝑘 2 (eq. 4)
providing evidence for the existence of a species with a short lifetime and a species with a longer lifetime absorbing at this wavelength. The short lifetime could be attributed to the absorption of 3 IC*, since the lifetime of this species increased with decreasing NaI concentration, leading to a decay similar to the decay of 3 IC* in pure water at that wavelength, and tending to be mono-exponential at low NaI concentrations (0.1 mM).

After comparison of absorption spectra at different times after the laser pulse, the absorption at 380 nm of the species with the longer lifetime could be observed several µs after the laser pulse and was stronger, though still low, than the absorption of a solution of IC in pure water (fig. 6). The comparison of the absorption spectrum of 3

4mM) registered at 8 µs after the laser pulse, showed as ---Δ, featuring a peak around 385 nm, not observed in the absorption spectrum of IC alone ( ■). At shorter times after the laser pulse (700 ns, insert), the spectrum of IC in presence of NaI (---Δ) is less intense at all wavelengths than the spectrum of IC only ( ■).

One of the products that are possibly formed by the atom radical I • is the radical anion I2 •-, formed by the combination of the anion with the oxidized halide radical. This well known transient species shows absorption maxima at 385 nm and at 725 nm is relatively stable, hence showing a long lifetime [START_REF] Devonshire | [END_REF][START_REF] Hug | Optical spectra of nonmetallic inorganic transient species in aqueous solutions[END_REF][START_REF] Ershov | [END_REF]. Our system did not permit to detect the second absorption peak of I2 •-at 725 nm, which intensity is expected to be 3.5 times lower than the intensity of the peak around 385 nm. The peak of I2 •-is low, despite the rather high molar absorption of this transient species (9600 cm -1 mol -1 ) [START_REF] Hug | Optical spectra of nonmetallic inorganic transient species in aqueous solutions[END_REF]. This could be explained by rapid I2

formation [40] or by fast scavenging reactions of I • and I2 •-, limiting the amount of I2 •- detected, as has been showed in the case of chloride [41]. These radical reactions are possible with the solvent or with the photosensitizer [42,5], which could explain the high absorption, even 8 µs after the laser pulse at wavelengths < 330 nm (fig. 6). The radical I2 •-is the only species expected to absorb at 380 nm and the peak can thus distinctively be attributed to this transient species. The absorption at shorter wavelengths cannot be completely monitored with our system and would not be characteristic for one expected transient species.

Bromide

The transient species formed after the photooxidation of bromide by 3 IC* were more difficult to follow, since the absorbance of one the expected products, Br2 •-, was overlapping with the absorbance of triplet state IC. Nonetheless, the fitted curves at the maximum absorption, 330 nm, of the triplet state IC, showed a mono-exponential decay in presence of bromide concentrations in the range of 1 -200 mM. The decay became bi-exponential for wavelengths around 354 nm, the maximum absorption of Br2 •-in water [43], indicating secondary product formation. As in the case of iodide, two species with distinct lifetimes could be distinguished, the short lived ascribed to the decay of 3 IC*. On the absorption spectrum (figure 7) taken 10 µs after the laser pulse, the absorption around 360 nm is higher in presence of bromide than the absorption obtained with IC alone. This could be due to the formation of Br2 -• , a strong absorbing radical species (εmax = 9900 M -1 cm -1 [40]) formed from the reaction of Br • with Br - . This absorption, detected only partially with our apparatus, shows a large peak with a rather long lifetime. Products contributing to this absorption could be recombination products of IC with Br • or the very strong absorbing Br3 -(εmax = 40 900 M-1 cm-1, λmax = 266 nm [44]).

The absorption of Br2 •-seems rather low, indicating that Br2 •-is not a major product of this photooxidative process. This could be due to Br2 formation or scavenging reactions of Br • and Br2 •-by the solvent or the photosensitizer [45]. One of the products possibly formed from the reaction of Br • with water is BrOH •- [45]. This radical shows a maximum absorption at 352 nm, very similar, but less intense, to the absorption Br2 •- [43], but the reaction of Br • with water is very slow (k = 1.4 s -1 , in [45]). Even if the absorption at this wavelength cannot be unambiguously ascribed to Br2 •-the formation of BrOH •-can thus be considered negligeable.

Proposed mechanism:

To resume the reactions and the formation of the products detected, the proposed mechanism involves the following reactions:

IC* + X -→ IC •-+ X • (R.1) X • + IC → products (R.2) X • + X -⇄ X2 •- (R.3) X2 •-+ IC → products (R.4) X2 •-+ X2 •-⇄ X3 -+ X - (R.5) X3 -⇄ X2 + X - (R.6) X • + X • → X2 (R.7) X2 •-+ X2 •-→ X2 + 2X - (R.8) X2 ⇄ X2 (g) (R.9)
This mechanism explains the formation of reactive radicals and can lead to the formation of halogen molecules in the gas phase.

Summary and atmospheric implications

Our results confirm the role of IC as photosensitizer proposed by Aregahegn et al. [11], for the first time evidencing the existence of a triplet state for this compound. The lifetime of 3 IC* is estimated at 1.21 µs in a deoxygenated aqueous solution and the maximum absorbance was measured at 330 nm.

The triplet state of IC was efficiently quenched by iodide, kq(I -) = (5.33 ± 0.25) ×10 9 M -1 s -1 , and much less by bromide, kq(Br -)= (6.27 ± 0.53) × 10 6 M -1 s -1 . Chloride showed a slow quenching rate, kq(Cl -) = (1.31 ± 0.16) × 10 5 M -1 s -1 and reactions with chloride might thus be negligible. Reactions with these halides form atomic halogens, some of which could be detected by increased transient absorption. Also, the quenching rate constants show the same trends as the oxidation potential of each sea salt anion, suggesting an electron transfer is the mechanism behind the photooxidation of the halides.

Imidazole-2-carboxaldehyde showed to be a quite efficient photosensitizer and, as IC can also be formed in aerosols in presence of glyoxal and ammonia, its presence, even in traces, could have an important influence on the particle phase chemistry at the interface of aerosols. Its photosensitized reactions can lead to an uptake of gas-phase VOCs and lead to particle growth, as demonstrated by the works in [11]. The photochemical radical production mechanism initiated by carbonyl compounds proposed in this study is potentially important in the SML, not only in reactions with sea salts but also for the oxidation of other organic compounds with a one electron oxidation potential. Indirectly, photochemistry evidenced for IC and other carbonyl compounds may also influence the chemistry of the SML by the radicals and secondary products formed during this process and the MBL by the release of reactive (halogenated) species, such as Br2, Br2 •-, I2 and I2 •-in the gas-phase [5,11].

A

  time-resolved study of the multiphase chemistry of excited carbonyls: Imidazole-2-carboxaldehyde and halides L. Tinel, S. Dumas, C. George To cite this version: L. Tinel, S. Dumas, C. George. A time-resolved study of the multiphase chemistry of excited carbonyls: Imidazole-2-carboxaldehyde and halides. Comptes Rendus. Chimie, 2014, 17 (7-8), pp.801-807. 10.1016/j.crci.2014.03.008. hal-01116221

  photomultiplier (Hamamatsu H7732-01). The PMT signal was passed through a high-speed

  25 mM IC in pure water showed strong transient absorptions, as shown in figure 1. The transient absorption of excited IC also shows intense fluorescence in the first nanoseconds after the laser pulse.Figure 2 shows recorded transient absorption spectra at different time intervals after the laser pulse, demonstrating the

Figure 1 :Figure 2 :

 12 Figure 1: Transient absorption decay obtained at 330 nm of the IC triplet state in a deoxygenated aqueous solution of 0.25 mM IC

Figure 3 :

 3 Figure 3: Log plot of a transient absorption decay obtained at 330 nm of the IC triplet state in a deoxygenated aqueous solution of 0.25 mM IC alone (■) and in presence of 0.25 mM NaI (▲) and the linear fits showing a greater slope in presence of NaIThe quenching rate coefficient kq(I -) obtained for 3 IC* by I -from the slope of the Stern-

Figure 4 :

 4 Figure 4: Stern-Volmer plot of the pseudo-first order rate coefficients kobs of IC triplet state quenching in function of the halide concentrations.

  radicals are very reactive, can form secondary products and give rise to transient product absorption. By establishing transient absorption spectra at different times after the laser pulse and for different concentrations of halogens, transient absorption products could be detected in presence of iodide and bromide. No radical product formation was observed following the excitation of IC in presence of chloride, since the quenching reaction with chloride was shown to be much slower.

Figure 5 :

 5 Figure 5: Transient absorption decay of 3 IC* (a) in presence of 300 mM NaBr (■) monitored at 355 nm and (b) in presence of 0.4 mM NaI (Δ) monitored at 380 nm, showing a biexponential decay.

  IC* in pure water with the absorption spectrum of 3 IC* in presence of 0.4 mM of NaI after shorter time intervals after the laser pulse, illustrated by the insert of figure 6, does not feature this enhanced absorption around 380 nm. This indicates clearly a secondary formation for the species absorbing at 380 nm.

Figure 6 :

 6 Figure 6: Absorption spectrum of IC (0.25 mM) in presence of NaI (0.4mM) registered at 8 µs after the laser pulse, showed as ---Δ, featuring a peak around 385 nm, not observed in the absorption spectrum of IC alone ( ■). At shorter times after the laser pulse (700 ns, insert), the spectrum of IC in presence of NaI (---Δ) is less intense at all wavelengths than the spectrum of IC only ( ■).

Figure 7 :

 7 Figure 7: Absorption spectrum of IC (0.25 mM) in presence of NaBr (300 mM) showing higher absorption around 360 nm (---Δ) than the absorption spectrum of IC alone ( ■), registered at 10 µs after the laser impuls. At shorter times after the laser impuls (400 ns, insert), the spectrum of IC in presence of NaBr (---Δ) is less intense at all wavelengths than the spectrum of IC only ( ■).

Figure 7

 7 Figure 7 also shows increased absorption for wavelengths shorter than 355 nm, even at

Figure 1 :Figure 2 :Figure 3 :Figure 4 :

 1234 Figure 1: Transient absorption decay obtained at 330 nm of the IC triplet state in a deoxygenated aqueous solution of 0.25 mM IC alone (■)

Figure 5 :

 5 Figure 5: Transient absorption decay of 3 IC* (a) in presence of 300 mM NaBr (■) monitored at 355 nm and (b) in presence of 0.4 mM NaI (Δ) monitored at 380 nm, showing a biexponential decay.

Figure 6 :

 6 Figure 6: Absorption spectrum of IC (0.25 mM) in presence of NaI (0.4 mM) registered at 8 µs after the laser pulse, showed as ---Δ, featuring a peak around 385 nm, not observed in the absorption spectrum of IC alone ( ■). At shorter times after the laser pulse (700 ns, insert),the spectrum of IC in presence of NaI (---Δ) is less intense at all wavelengths than the spectrum of IC only ( ■).

Figure 7 :

 7 Figure 7: Absorption spectrum of IC (0.25 mM) in presence of NaBr (300 mM) showing higher absorption around 360 nm (---Δ) than the absorption spectrum of IC alone ( ■), registered at 10 µs after the laser impuls. At shorter times after the laser impuls (400 ns, insert), the spectrum of IC in presence of NaBr (---Δ) is less intense at all wavelengths than the spectrum of IC only ( ■).

Acknowledgement

This study has been with funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement 290852 -AIRSEA.