935 research outputs found
Elastic instability in stratified core annular flow
We study experimentally the interfacial instability between a layer of dilute
polymer solution and water flowing in a thin capillary. The use of microfluidic
devices allows us to observe and quantify in great detail the features of the
flow. At low velocities, the flow takes the form of a straight jet, while at
high velocities, steady or advected wavy jets are produced. We demonstrate that
the transition between these flow regimes is purely elastic -- it is caused by
viscoelasticity of the polymer solution only. The linear stability analysis of
the flow in the short-wave approximation captures quantitatively the flow
diagram. Surprisingly, unstable flows are observed for strong velocities,
whereas convected flows are observed for low velocities. We demonstrate that
this instability can be used to measure rheological properties of dilute
polymer solutions that are difficult to assess otherwise.Comment: 4 pages, 4 figure
THE EFFECTS OF COUNTERFEIT ON LUXURY BRAND BUYING BEHAVIOR, IN TERMS OF CONSUMPTION EXPERIENCE
A large number of studies on counterfeiting explore consumer behaviors in the consumption of counterfeit articles. But few of them consider luxury brand consumers and counterfeiting. Our research attempts to contribute to this field by studying strategies adopted by luxury brand consumers in the face of counterfeiting (Commuri 2009). To do so, we use the concept of an "experience of another self" in buying a product (Dampérat et al., 2002), which focuses on personal and social objects of consumption.Counterfeit consumption, Luxury brand, Consumption experience
The impact of step-down line extension on consumer-brand relationships: A risky strategy for luxury brands
This paper analyzes the role of the brand concept (luxury vs. non-luxury) in the impact of step-down line extension on consumer-brand relationships. A before-and-after pseudo-experimental study conducted on the Internet among BMW and Peugeot buyers shows that step-down line extension negatively influences the main variables of consumer-brand relationships (e.g., self-brand connections, brand attachment, brand trust and brand commitment) only for the luxury brand BMW. On the contrary, no dilution effects are found for the non-luxury brand Peugeot.vertical line extension, dilution effects; consumer-brand relationships;luxury brands; cars; PSL approach
Formal specification of a self-sustainable holonic system for smart electrical micro-grids
Stand-alone micro-grids have emerged within the smart grids field, facing important challenges related to their proper and efficient operation. An example is the self-sustainability when the micro-grid is disconnected from the main utility, e.g., due to a failure in the main utility or due to geographical situations, which requires the efficient control of energy demand and production. This paper describes the formal specification of a holonic system architecture that is able to perform the automation control functions in electrical stand-alone micro-grids, particularly aiming to improve their self-sustainability. The system aims at optimizing the power flow among the different electrical players, both producers and consumers, to keep the micro-grid operating even under adverse situations. The behaviour of each individual holon and their coordination patterns were modelled, analysed and validated using the Petri net formalism, allowing the complete verification of the system correctness during the design phase.info:eu-repo/semantics/publishedVersio
Quand l'information échappe à ses créateurs : le cas de l'artificialisation des terres agricoles en Languedoc-Roussillon
International audienceThis article aims to describe how the quantification of a phenomenon in relation to a specific worldview spreads and is distorted. This project has been supported by a regional public authority in Languedoc-Roussillon (France), and consisted in the production of information so to quantify and qualify the farmland decrease due to urban sprawl. The paper is based on Latour's actor-network theory; it characterizes the process of enrolment, and the development of dissidences. Identifying contradictory logics and dissidences help questioning the complexity of âclosing the black-box' regarding information production and of sensemaking between heterogeneous actants involved in a supposed-to-be public debate.Cet article vise Ă spĂ©cifier comment la quantification d'un phĂ©nomĂšne fondĂ©e sur une certaine vision du monde se propage et se dĂ©forme. Ce projet a Ă©tĂ© portĂ© par une direction dĂ©concentrĂ©e de l'Etat soucieuse de l'emprise croissante du bĂąti sur les terres agricoles en Languedoc-Roussillon. Le cadre thĂ©orique mobilisĂ©, la sociologie de la traduction, permet d'identifier les grandes Ă©tapes d'intĂ©ressement, d'enrĂŽlement, ainsi que le dĂ©veloppement de controverses. Les difficultĂ©s rencontrĂ©es interrogent sur la complexitĂ© de clĂŽture de processus innovants s'agissant de production d'information et de co-construction de sens associant des actants hĂ©tĂ©rogĂšnes impliquĂ©s dans des procĂ©dures de dĂ©bat public
On the variability of the slow solar wind: New insights from the modelling and PSP-WISPR observations
We analyse the signature and origin of transient structures embedded in the
slow solar wind, and observed by the Wide-Field Imager for Parker Solar Probe
(WISPR) during its first 10 passages close to the Sun. WISPR provides a new
in-depth vision on these structures, which have long been speculated to be a
remnant of the pinch-off magnetic reconnection occurring at the tip of helmet
streamers. We pursue the previous modelling works of Reville (2020b, 2022) that
simulate the dynamic release of quasi-periodic density structures into the slow
wind through a tearing-induced magnetic reconnection at the tip of helmet
streamers. Synthetic WISPR white-light (WL) images are produced using a newly
developed advanced forward modelling algorithm, that includes an adaptive grid
refinement to resolve the smallest transient structures in the simulations. We
analyse the aspect and properties of the simulated WL signatures in several
case studies, typical of solar minimum and near-maximum configurations.
Quasi-periodic density structures associated with small-scale magnetic flux
ropes are formed by tearing-induced magnetic reconnection at the heliospheric
current sheet and within 3-7Rs. Their appearance in WL images is greatly
affected by the shape of the streamer belt and the presence of
pseudo-streamers. The simulations show periodicities on the ~90-180min, ~7-10hr
and ~25-50hr timescales, which are compatible with WISPR and past observations.
This work shows strong evidence for a tearing-induced magnetic reconnection
contributing to the long-observed high variability of the slow solar wind.Comment: 23 pages, 14 figures, to appear in Astronomy & Astrophysics,
associated movies available at https://doi.org/10.5281/zenodo.813559
L'appréciation de la fécondité des taureaux à l'insémination artificielle : étude sur quelques problÚmes relatifs à la mesure des facteurs de diffusion du sperme par méthode biologique
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