Strategic Adoption of a New Technology under Uncertain Implementation

Les entreprises américaines investiront en 1997 quelque 50 milliards de $dans des projets de réingénierie dont les deux-tiers s'avéreront, semble-t-il, des échecs, à cause principalement de la résistance au changement et du manque de concensus et d'engagement de la part des hauts dirigeants. Or, notre connaissance des différences stratégiques entre l'adoption d'une nouvelle technologie et son implantation réussie reste fort limitée. Nous inspirant d'un modèle proposé par Stenbacka et Tombak (1994), nous considérons les effets de divers facteurs sur les dates d'adoption de la nouvelle technologie choisies par les doupoleurs, tels de meilleurs programmes d'implantation, des gains relatifs plus élevés d'adopter en premier (et en second), et des coûts d'investissements à l'adoption plus faibles.American corporations will spend some$50 billion US in 1997 on reengineering projets. It is believed that two thirds of these efforts will end up in failure because of significant resistance to change and a lack of concensus and commitment among senior executives. Very little effort has been exerted to foster our understanding of the strategic differences between adopting and implementing a new technology. Building on a model first proposed by Stenbacka and Tombak (1994), we show how the adoption timing decisions in a sequential duopoly structure are affected by more efficient implementation programs, higher relative gains of being the first (and second) to successfully implement the technology, and lower relative investment costs of adopting the new technology

Strategic Adoption of a New Technology under Uncertain Implementation

American corporations will spend some $50 billion US in 1997 on reengineering projets. It is believed that two thirds of these efforts will end up in failure because of significant resistance to change and a lack of concensus and commitment among senior executives. Very little effort has been exerted to foster our understanding of the strategic differences between adopting and implementing a new technology. Building on a model first proposed by Stenbacka and Tombak (1994), we show how the adoption timing decisions in a sequential duopoly structure are affected by more efficient implementation programs, higher relative gains of being the first (and second) to successfully implement the technology, and lower relative investment costs of adopting the new technology. Les entreprises américaines investiront en 1997 quelque 50 milliards de$ dans des projets de réingénierie dont les deux-tiers s'avéreront, semble-t-il, des échecs, à cause principalement de la résistance au changement et du manque de concensus et d'engagement de la part des hauts dirigeants. Or, notre connaissance des différences stratégiques entre l'adoption d'une nouvelle technologie et son implantation réussie reste fort limitée. Nous inspirant d'un modèle proposé par Stenbacka et Tombak (1994), nous considérons les effets de divers facteurs sur les dates d'adoption de la nouvelle technologie choisies par les doupoleurs, tels de meilleurs programmes d'implantation, des gains relatifs plus élevés d'adopter en premier (et en second), et des coûts d'investissements à l'adoption plus faibles.Technology adoption, implementation, duopoly, Adoption de technologie, implantation, duopole

A new optical set-up for on-line following up the crystallization of polymers at high cooling rates

International audienceA new experimental procedure, named " Polymer High Cooling - Optics " and whose performance has been improved, is presented. It allows us to monitor on-line the quiescent crystallization of a polymer film under high and constant cooling rates. With such a set-up, two cooling control modes are available resulting into a range of relatively moderate (from 30 to 500°C/min) and a range of high (from 500 to 1600°C/min) constant cooling rates. The crystallization experiments are observed by polarized light microscopy. Preliminary results are presented. They are obtained on the α-modification of one industrial grade of isotactic polypropylene, under relatively moderate constant cooling rates. Two relevant crystallization parameters are captured, the temperature of crystallization together with the spherulitic growth kinetics versus cooling rate. Accurate data are obtained. As well, they are in good agreement with comparable literature results compiled by Janeschitz-Kriegl [Macromolecules, 2006]. The obtained results seem to match the Hoffman and Lauritzen theory. These discussions validate our " Polymer High Cooling - Optics " set-up in relatively moderate constant cooling rates. Next step is to demonstrate the suitability of this first generation set-up for higher constant cooling rates

Crystallization kinetics of polypropylenes. Effect of nucleating agents?

International audienceThermal conditions and formulation affect the crystallization mechanisms of polymers and the associated kinetics in a coupled manner. In that field, the objective of this investigation is to compare overall crystallization kinetics and structural organization of one clarified polypropylene (specifically designed for stretch-blow molding) and a homopolypropylene. Liquid/solid transitions are investigated in- and ex-situ under isothermal and non-isothermal conditions combining crossed-polarized optical microscopy, differential scanning calorimetry and X-ray diffraction. Clarified polypropylene has a very 'singular behavior' compared to homopolymer since no spherulites can be observed. However, it exhibits a semi-crystalline structure. The major α-phase coexists with some γ-phase even under quiescent conditions. Overall crystallization kinetics is rapid suggesting the existence of very efficient nucleating agent(s) and resulting in an increase of crystallization temperature. In parallel, the melting temperature of copolymer decreases by 20 °C compared to homopolymer, suggesting a drastic change in lamellae thickness. It is concluded that this unusual structure results from nucleation, which enforces high temperature crystallization, and copolymerization, which constraints the crystalline organization

Polymer Microstructures. Modification and Characterisation by Fluid Sorption

International audiencePolymer micro-organisation can be modified by combination of the three constraints, thermal, hydrostatic and fluid sorption. In selecting the fluid's nature, chemically active or inert, and its physical state, liquid or supercritical, new “materials” can be generated. In addition, the interplay of temperature and pressure allows tailoring the obtained material structure for specific applications. Several complementary techniques have been developed to modify, analyze and characterize the end products: scanning transitiometry, vibrating wire (VW)-PVT coupling, thermoporosimetry, temperature modulated DSC (TMDSC), sorptometry. The great variety of possible applications in materials science is illustrated with different polymers which can produce materials from soft gel to rigid foams when submitted to fluid sorption, typical fluids being methane, or a simple gas (CO2 or N2). Absorption of an appropriate fluid in a cross linked polymer leads to a swelling phenomenon. Thermoporosimetry is a calorimetric technique developed to measure the shift by confinement of thermal transition temperatures of the swelling fluids, which can be currently used solvents or mercury. Application of thermoporosimetry to a swollen cross linked polymer allows to calculate the mesh size distribution and to evaluate the degree of reticulation of the polymer. The same technique can be applied to characterise the pore size distribution in a foamed polymer

Numerical simulation of boiling during the quenching process

National audienceDuring the thermal modelling of the quenching process, different stages of boiling need to be treated, from nucleate boiling to generation and growth of a vapour film. The interface between each phase flow is determined using a level set method. Surface tension is evaluated using the continuum surface force. The proposed approach demonstrates the capability of the model to simulate detachment of a single bubble and the generation of film vapour from a heated source. A comparison between numerical and experimental results shows a good agreement.br/>See http://hal.archives-ouvertes.fr/docs/00/59/26/76/ANNEX/r_71D43983.pd

How to determine the parameters of polymer crystallization for modeling the injection-molding process?

International audienceTo understand the relationship between 'polymers-processing conditions-structures-properties', crystallization is one of the major concerned phenomena. A general crystallization model derived from Avrami's work has been developed at CEMEF and implemented into a 3D finite element code for injection-molding named Rem3D®. It gives a precise description of the crystallization event, allows the determination of morphological features, but it requires a reliable determination of the crystallization parameters. The experimental procedures adopted to capture relevant experimental parameters are presented. The determination of overall kinetics, density of potential nuclei with activation frequency of nuclei into crystalline entities, and growth rate is carried out with polarized optical microscopy (POM) and is supplemented by small angle light scattering (SALS). The treatment of data is performed by a classical method or using an inverse genetic algorithm method to extract the parameters necessary to our model. The 2D simulation of the crystallization, illustrated with Rem3D®, reproduces the experimental reality quite accurately, in the case of an isothermal and static crystallization. This is applied to two polymers, an isotactic homopolymer polypropylene iPP and a polyether-block amide PEBAX®

Thermodynamics and Thermokinetics to Model Phase Transitions of Polymers over Extended Temperature and Pressure Ranges Under Various Hydrostatic Fluids

We are grateful to InTech the publisher of the book "Thermodynamics - Interaction Studies - Solids, Liquids and Gases", for letting this publication being archived in this Open Access repository. The publication is available from Intech Open Access Publisher: http://www.intechopen.com/articles/show/title/thermodynamics-and-thermokinetics-to-model-phase-transitions-of-polymers-over-extended-temperature-aInternational audienceA scientific understanding of the behaviour of polymers under extreme conditions of temperature and pressure becomes inevitably of the utmost importance when the objective is to produce materials with well-defined final in-use properties and to prevent the damage of materials during on-duty conditions. The proper properties as well as the observed damages are related to the phase transitions together with intimate pattern organization of the materials. Thermodynamic and thermokinetic issues directly result from the thermodynamic independent variables as temperature, pressure and volume that can stay constant or be scanned as a function of time. Concomitantly, these variables can be coupled with a mechanical stress, the diffusion of a solvent, and/or a chemically reactive environment. A mechanical stress can be illustrated in a chemically inert environment by an elongation and/or a shear. Diffusion is typically described by the sorption of a solvent. A chemical environment is illustrated by the presence of a reactive environment as carbon dioxide or hydrogen for example. Challenging aspects are polymer pattern multi scale organizations, from the nanometric to the macrometric scale, and their importance regarding industrial and technological problems, as described in the state of the art in Part 2. New horizons and opportunities are at hands through pertinent approaches, including advanced ad hoc experimental techniques with improved modelling and simulation. Four striking illustrations, from the interactions between a solvent and a polymer to the growth patterns, are illustrated in Part 3

Pelagic population dynamics of Aurelia sp in French Mediterranean lagoons

The pelagic dynamics of the cosmopolitan scyphozoan Aurelia sp. was investigated in three French Mediterranean lagoons, Thau, Berre and Bages-Sigean, which harbour resident populations. The annual cycles showed a common univoltine pattern in all lagoons where the presence of pelagic stages in the water column lasted similar to 8 months. Field observations showed a release of ephyrae in winter time followed by pronounced growth between April and July, when individuals reached the largest sizes, before disappearing from the water column. Maximum abundance of ephyrae and medusae were registered in Thau. Medusae abundance attained a maximum of 331 ind 100 m(-3) in Thau, 18 ind 100 m(-3) in Berre and 7 ind 100 m(-3) in Bages-Sigean lagoons. Temperature and zooplankton abundance appeared as leading factors of growth, where Bages-Sigean showed the population with higher growth rates (2.66 mm day(-1)) and maximum size (32 cm), followed by Thau (0.57-2.56 mm day(-1); 22.4 cm) and Berre (1.57-2.22 mm day(-1); 17 cm). The quantification of environmental windows used by the species showed wider ranges than previously reported in the Mediterranean Sea, which suggests a wide ecological plasticity of Aurelia spp. populations in north-western Mediterranean lagoons.GELAMED project; Total foundation [189 - "Recherche" 18902 C]; EC2CO "Ecosphere Continentale et Cotiere" programme through the DYNAMO project; OSU-OREM

Application of two-color LIF thermometry to nucleate boiling

International audienceThe laser-induced fluorescence (LIF) thermometry is applied to measure the temperature field surrounding a single vapor bubble growing at an artificial nucleation site. In order to correct measurement errors due to the non-uniformity of the incident laser intensity, the two-color LIF thermometry technique is used in this nucleate boiling experiment. This technique is based on the use of two fluorescent dyes: the temperature sensitive dye Rhodamine B and the temperature insensitive dye Sulforhodamine-101. The concentration of the dyes is optimized by analyzing the behavior of fluorescence intensities. The mapping between the two images is determined through a geometrical calibration procedure. This technique presents a success in correcting the non uniformities due to the reflection of the light at the bubble surface and to the temperature gradient. The obtained temperature fields show that the two-color LIF is a promising technique in the investigation of nucleate boiling