Upscaling Flow and Transport Processes

Peer reviewe

Renegotiation of joint venture contracts: The influence of boards of directors and prior ties as alternative governance mechanisms

Research on alliance governance has pointed out that joint ventures (JVs) are particularly complex forms of collaboration. Partnering firms therefore often face difficulties in anticipating contingencies and collaborative behaviors at the contract negotiation stage. When initial JV contracts are incomplete, renegotiation represents a key strategic opportunity for enhancing contractual safeguards or coordination guidelines over the course of the joint venture. Costs and risks entailed by renegotiating JV arrangements at a later stage are far from trivial, however. Existing research on alliances suggests that practitioners have alternative relational and formal governance solutions at their disposal for handling possible inefficiencies caused by contractual gaps over time. Although insightful, this research does not enable a determination as to whether these alternative relational and formal mechanisms substitute for or facilitate ex post contractual renegotiation. The competing arguments found in the literature provide little guidance to JV practitioners as well. Our results show that the collaborative context within which the JV is embedded (i.e., prior inter-partner ties) obviates the need for enhancing incomplete JV contracts ex post. By contrast, ex post contractual adjustments are fostered and facilitated by the formal and administrative apparatus engaged over the course of the JV (i.e., an involved JV board of directors). Such opposing effects suggest that prior ties can “prevent” the occurrence of inefficiencies caused by contractual gaps, while an involved JV board primarily can act as a mediation and renegotiation platform to “repair” the exchange when inefficiencies occur. Our findings highlight the multidimensional nature of joint venture governance, and in particular the interplay among various formal and informal governance solutions in the execution of joint ventures. By unpacking their complex effects on the decision to renegotiate incomplete JV contracts, our study also holds important value for managers seeking to govern their JVs over time

3D reconstruction of dynamic liquid film shape by optical grid deflection method

In this paper, we describe the optical grid deflection method used to reconstruct the 3D profile of liquid films deposited by a receding liquid meniscus. This technique uses the refractive properties of the film surface and is suitable for liquid thickness from several microns to millimeter. This method works well for strong interface slopes and changing in time film shape; it applies when the substrate and fluid media are transparent. The refraction is assumed to be locally unidirectional. The method is particularly appropriate to follow the evolution of parameters such as dynamic contact angle, triple liquid-gas-solid contact line velocity or dewetting ridge thickness

The use of halide charged interleaves for treatment of iron gall ink damaged Papers

International audienceIn certain conditions, iron gall inks induce substantial damages on cellulosic supports. Existing curative treatments necessitate the immersion of the documents in aqueous solutions. This implies several undesirable side effects: mechanical stress of the most damaged papers, substantial colour changes, and a drastic modification of the paper/ink composition. This work investigated an alternative treatment that consists in compressing the document between two interleaves that are charged with active compounds. When this operation is operated in moist conditions, active compounds may migrate from the interleaves to the document, and thus achieve the treatment of the paper. As high humidity conditions may additionally induce some migration of iron and acidic compounds out of the ink line, it first appeared necessary to research humidity conditions which minimize these undesirable migrations. This investigation was performed on a set of 53 original manuscripts and led us to consider that a relative humidity of 80% was quite reasonable. The second part of the paper deals with the evaluation of interleaving treatment efficiency. It was performed on laboratory samples, using several types of antioxidant halide salts (NaCl, NaBr, CaBr 2) (halides are known to act as radical scavengers). These compounds were tested separately or in combination with calcium carbonate as an alkaline buffer. The samples were made of Whatman paper that was preliminary impregnated with iron gall ink. It has shown that a charge of 2% calcium carbonate in the interleaves has no impact on the treatment efficiency, which mainly depends upon the concentration of salts, the contact pressure and the duration of the treatment. Elemental measurements show that the mobility of the salts is much higher than that of iron, suggesting the possibility to find optimum treatment conditions that minimize the iron migration risk while achieving an effective migration of halides